Introduction
This article deals with the contention of whether or not the prophets and the messengers of Allah are infallible (sinless). In Part 1, we will examine the Sunni point of view, and then we will present the Shia opinion on the matter with reference to the verses of Quran. In Part 2, we will provide logical reasoning behind the issue of the infallibility. In addition, we look at some of the authentic Sunni traditions in support of the infallibility. In Part 3, we respond to the arguments of the opponents in this regard.
Is it possible for a human being to be sinless? Is it realistic to believe that Allah (SWT), the Creator and Sustainer of the Universe, would send forth a sinful man to guide mankind? What about the Quran, what information and evidence about the matter does it provide? These are the questions, among others, that the article at hand is attempting to answer.

Disclaimer
The Twelver Shi'ites do NOT hold ANY human being, whether he be a prophet, a messenger, or an Imam, to be divine. We do not worship human beings, nor do we approve of such a custom. Allah (SWT) is never compromised in Shi'ite theology or philosophy! All the negative stuff you may hear about us is pure propaganda with political motives.
Allah (SWT) is Exalted above all that scratches dignity and justice. We hold Allah (SWT) to be the JUST Creator (SWT), Who never commits any injustice against His creation. Allah (SWT) is indivisible, and He does not relinquish His (SWT) Majesty and Sovereignty to anyone. No one is permitted to interfere with His Wishes, except by His leave. This is the Authentic Twelver Shi'ite Creed, and everything else that is negative in nature, and is attributed to the Shia, is crap.

Infallibility According to the Sunnis
The Sunni scholars do not speak in one voice on this subject. Some Sunnis claim that the Prophet(S.A.W.) is sinless or infallible ONLY in the delivery of Allah's message. Other than that, he(S.A.W.), just like others, sins and makes mistakes in many things.
This faction of Sunnis base their opinion on the traditions narrated in their books about how the Prophet(S.A.W.) falls asleep and forgets the prayer time, and even forgets to perform the necessary ablution (Wudu) for prayer (Sahih al-Bukhari, Arabic version, v1, p37,44,171). Furthermore, they claim that he(S.A.W.) used to sit with Aisha and watch a dance with music (Sahih al-Bukhari, Arabic version, v3, p228). They also claim that he(S.A.W.) was affected by a magical spell that caused severe episodes of hallucination on his part (Sahih al-Bukhari, Arabic version, v7, p29; and v4, p68). These are but a FEW of the most heinous of acts that these "scholars" attribute to the Mercy to Mankind, the Messenger of Allah, Muhammad(S.A.W.).
Note that according to the Shia, these traditions are NOT authentic, nor do they constitute ANY truth whatsoever. Again, these traditions were inserted into their books by the Umayad, among others, to justify their own corruption and insolence. For when the Prophet(S.A.W.) sins so heinously as they depict him(S.A.W.) in the above traditions, we can no longer blame Uthman, or Muawiyah, or Yazid, or Amr Ibn al-Aas, among others, when they sin. It is to their advantage to portray the Prophet(S.A.W.) as a man who listens to music and watches a dance with his wife, to justify the dancing and the music that was (and still is) rampant in their palaces.
The current state of the Ummah is NOT because a few of us aren't praying or fasting,; it is because some people have CHANGED and MUTILATED the religion of Allah (SWT) to satisfy their lusts, just like the Christians and Jews did. That's exactly what we have fallen into. We sin, then we say: so what -- the Prophet(S.A.W.) himself was a sinner! Purified be the prophets and messengers of Allah (SWT) from being of such a sinful nature! By Allah, to say such a thing is more of an insult to Allah, than it is to the prophet and messengers.
Because when we assert that Allah sends forth sinful men, we are claiming that Allah (SWT) Himself approves of sin; or why, then, would he send forth a sinful man? Yet, on the other hand, Allah (SWT) forbids us from doing evil! What kind of twisted logic is this? Exalted be Allah (SWT) from such an insult!

Infallibility According to the Shia
The Shia, on the other hand, state that ALL the prophets and messengers of Allah, with NO exception, are sinless and infallible, even before they became prophets and messengers. For instance, although Prophet Muhammad(S.A.W.) became Messenger at the age of forty, the Shia assert that even in the first forty years of his life, he was sinless and infallible -- an assertion that history attests to as well. It is indeed frustrating to conceive of a human being who is NOT sinful. So, let us first define the concept of infallibility:

The Concept of Infallibility
According to the scholar Muhammad Jawad Mughniyah (May Allah rest his soul in peace), in his book "al-Islam Wa al-'Aql -- Islam and Reason," the concept of Ismah (Infallibility) is very often misunderstood. What we mean by that concept is that a prophet, by virtue of his prophethood, has a pure soul. As the Quran states:
"...the (human) soul certainly incites evil, UNLESS my lord do bestow His Mercy... (12:53)"
Clearly Allah (SWT) has made an exception (by using the term "UNLESS") to the human soul that incites evil. We can understand, based on Shi'ite philosophy, that the attachment of the soul (Nafs) to being is that of a relationship of control and administration. Therefore, the soul may incite evil; but the individual has the freedom and the authority to reject that invitation to evil. If the individual accepts the invitation to evil, he becomes accountable for that evil which he commits. This is a very simplified explanation, but it serves the purpose.
Now, the prophets or the messengers, are among the exception as Allah (SWT) has indicated. That is, there is something in the soul of these virtuous HUMANS that precludes the incitement of evil, and as such they never commit it. Their virtue is so high that they never even think of committing a sin. It is NOT that if a prophet or a messenger wanted to commit a sin, he can't; rather, it is that "Mercy," mentioned in the above verse, that is bestowed upon him from Allah (SWT) that precludes him from doing so. As such, he is sinless and infallible even though they have full ability of committing any kind of sin.
When Satan refused to prostrate to Adam, He was driven away and became an accursed one. Quran states that thereupon Satan said: 15:39
He said: My Lord, Because You has sent me astray, verily I shall adorn the path of error for them on the earth, and shall deceive them all. 15:40
Except those of them who are Your perfectly devoted Servants. 15:41
(Allah) said: "This (Way of My sincere servants) is indeed a Way that leads straight to Me. 15:42
Lo! as for My slaves, you have NO way into them except the wrong-doers who follow you. 15:43
And verily for all such people, hell is the promised place. It is clear from the above conversation that Allah has promised that Satan has NO WAY into His sincere Servants, and only wrong-doers will follow the Satan. Thus the Sincere Servants of Allah are not wrong-doers and shall not be deceived. Also Allah confirms that the Path of His Sincere Servants is a path which leads straight to Him. All these facts prove that the Sincere Servants of Allah never fall into the trap of Satan, and as such they are infallible, due to Allah's Mercy.
One side remark here is that there is no mention of "prophet" or "messenger" in the above verses. In other words, the "perfectly devoted Servants" who are infallible are not necessarily "prophets" or "messengers". The issue of the infallibility of the Imams will be discussed in a separate article, however.

The Quran Speaks About the Prophets
First, it would be of help to take a look at the commandment of obeying the messenger, to see how all-encompassing and all-pervading this commandment is, and how great the authority of the messenger of Allah is. Allah states in Quran:
"And we did not send any messenger, unless he should be obeyed by Allah's authority." (Quran 4:64)
The prophet or the messenger of God is to be obeyed and followed; the followers ARE NOT EXPECTED TO CHECK EVERY ORDER OF THE PROPHET to decide what is to be obeyed and what is not to be obeyed. There is no way to check his commands, because he himself gave us all the rules and divine laws in the form of Scripture and his traditions (sayings/actions/satisfactions). If we become suspicious to some of the actions of the prophet, this suspicion can cause all his commands and laws that he has already conveyed to go under question. This shows that the prophets and messengers were free from error and sin; otherwise Allah would not have ordered people to obey them UNCONDITIONALLY.
There are many verses in which Allah commands us to obey the prophet:
"O you who believe! Obey Allah, and obey the Messenger and do not burn your deeds (by disobeying him)." (Quran 47:33) Allah, Exalted, also states:
"Whoever obeys the Messenger, he indeed obeys Allah." (Quran 4:80)
In the above verses as well as many other verses of the Quran, obedience of Allah has become synonymous with the obedience of the prophets. Such assertion would have been impossible if the prophets were not infallible (Ma'soom). Now, note the following verse:
"....and obey not from among them a sinner or an ungrateful one." (Quran 76:24)
The picture is complete! "The prophets are to be obeyed," and "the sinners are NOT to be obeyed." The only conclusion is that the prophets were NOT sinners or wrong-doers. In other words, they were infallible (Ma'soom) and sinless.
Looking specially at the Holy Prophet of Islam(S.A.W.), Allah tells us:
"And whatever the Messenger gives you, take it; and from whatever he forbids you, keep back." (Quran 59:7)
This is another indication that WHATEVER the Prophet(S.A.W.) offered must be accepted unconditionally and with no doubt. This means that the permission or prohibition of the Holy Prophet was always in accordance with the will of Allah and was always favored by Him. It proves that the Holy Prophet was protected (Ma'soom). No one can be so sure about the commands of a man who is not infallible.
Now, if the Prophet(S.A.W.) was a sinner as some people falsely allege, then how can Allah (SWT) order us to accept that which could be sinful? Fear Allah (SWT) in your reasoning. For those who argue that the above verse is specific ONLY to religious injunctions, and the Prophet(S.A.W.) is sinless in that matter only, I would say such assertion is baseless. This is a basic rule that to the time that there is no exclusion or condition or particularization has been mentioned in conjunction with a text of Quran, it covers all aspects.
Second, EVERYTHING the Prophet(S.A.W.) spoke had something to do with Allah (SWT) and His religion; then how can you claim that Allah (SWT) is making a separation? Haven't you heard what Aisha said when she was asked about the Prophet's behavior? She said: "His life was the Quran, especially the first ten verses of the Chapter al-Noor, the Light." Now, if the Prophet's(S.A.W.) life was the Quran verbatim, how can he(S.A.W.) be a sinner? That means that the Quran is full of sinful things! Exalted be Allah (SWT) from revealing such a book!!! There is another verse in which Allah said:
"(O prophet) tell (people) If you really love Allah, then follow me, Allah will love you and forgive you your sins." (Quran 3:31) Here the love of Allah is made contingent on following the orders of the Prophet of Islam. Both sides of love are included in it. If you love Allah follow the Prophet; if you follow the Prophet, Allah will love you. Does it not show that the Prophet was absolutely free from any type of blemish? Not only the orders of the Prophet, but also all his decisions are protected from error for Allah said to his Prophet:
But no by thy Lord! They can have no (real) Faith until they make thee judge in ALL disputes between them and find in their souls no resistance against thy decisions but accept them with the fullest conviction. (Quran 4:65)
If ALL the decisions of the Prophet should be accepted unconditionally, then the Prophet should be protected from error in ALL his decisions. Beside his actions and his decisions, even any single word of his speeches was the Commands of Allah. Almighty states in the Quran: 53:1
By the Star when it sets, 53:2
Your companion (i.e., Prophet) does not err/wander, nor is he deceived 53:3
Nor does he speak out of his desire; 53:4
It is no less than a revelation that is revealed. 53:5
The Mighty in Power has taught him. The above verses not only proves that the Prophet did not err or sin, but also testifies that all his speeches were revelation (either directly or indirectly).
These verses unequivocally clears the Messenger of Allah(S.A.W.) from EVER saying ANYTHING of his(S.A.W.) own desire. That includes his(S.A.W.) tradition and the Quran. For those who argue otherwise, don't forget that the tradition is used in ANY interpretation of the Quran; and in matters of Jurisprudence (Fiqh), as well as in other areas. If the tradition is corrupt because you claim that the Prophet(S.A.W.) is a sinner (May Allah forgive us!!
, then the interpretation of the Quran is also corrupt!!! Fear Allah (SWT) in your reasoning! For those who claim that the Prophet(S.A.W.) is sinless in the delivery of the Message of Allah (SWT), and that includes the Hadith, then you have already admitted what the Shia say!!! It is unanimously agreed that the Sunnah of the Prophet covers the Prophet's sayings, actions, and thought/satisfaction. Since the Sunnah are reflections of the Prophet's actions, he(S.A.W.) is then sinless in the actions as well.
Allah also said:
"Have We not caused thy bosom to dilate? And removed from thee thy burden? That which weighed down thy back? And exalted the esteem (in which) thou (art held)?..." (Quran 94:1-4)
I will not personally comment on the above verse, but here's what Abdullah Yusuf Ali, a Sunni translator of the Quran, has to say in his footnotes to the verse:
"(This is also) the prayer of Moses (asking for the expansion of the breast). The breast is symbolically the seat of knowledge and the highest feelings of love and affection, the treasure-house in which are stored the jewels of that quality of human character which approaches nearest to the divine. The holy Prophet's human nature had been PURIFIED, EXPANDED, and ELEVATED, so that he became a Mercy to all Creation. Such a nature could afford to ignore the lower motives of ordinary humanity which caused shameful attacks to be made on him.
Its strength and courage could also bear the burden of the galling work which it had to do in DENOUNCING SIN, SUBDUING IT, and protecting Allah's (SWT) creatures from its oppression.
It is indeed a grievous and galling burden for a man to fight single- handed against sin. But Allah sends HIS GRACE and aid, and THAT BURDEN IS REMOVED, or converted into joy and triumph in the service of the One True God.
The Prophet's virtues, the magnanimity of his character, and his love for mankind were fully recognized in his lifetime, and his name stands highest among the heroic leaders of mankind. The phrase used here is more comprehensive in meaning that used for various prophets..." [End of quote from A. Yusuf Ali]
Do I need to say more? Let us see if Allah said any more:
"It is He who has sent His Messenger with the GUIDANCE and the Religion of Truth..." (Quran 9:33) "And the unbelievers say: Why is not a Sign sent down to him from his Lord? But thou art truly a warner and for EVERY nation there exists a GUIDE." (Quran 13:7)
A Messenger, who rehearses to you the Signs of Allah containing clear explanations, in order to lead forth those who believe and do righteous deeds from the depths of Darkness into Light." (Quran 65:11)
The above verses of Quran testify that the Prophet Muhammad(S.A.W.) was a Guide sent to lead forth people from the depths of Darkness into Light. (65:11) And that he(S.A.W.) is a warner (27:91) and one of the guides for people. (13:7). Sin is darkness, and as such, how can the Prophet was sent to move people from darkness into light when he himself is sitting in the darkness?! May Allah protect us from slandering His Prophet(S.A.W.). Similarly Quran informs us that the Prophet has come to us to sanctify and cleanse us and to teach us wisdom:
As We have sent unto you a messenger from among you who recites unto you Our revelations and cleanses you, and teaches you the Scripture and wisdom, and teaches you that which you knew not. (Quran 2:151)
Allah did bestow a great favor unto the believers when He sent among them an Messenger from among themselves reciting unto them the Signs of Allah sanctifying them and teaching them the Scripture and Wisdom while before that they had been in manifest error. (Quran 3:164)
See also Quran 2:129, 62:2 which also testify that one of the missions of the Prophet(S.A.W.) was to cleanse the true believers. Then how could a prophet purify others of wrong-doings if he himself were not pure? How could Allah send an impure and sinful person to cleanse others? How could a man teach others wisdom if he had no wisdom to distinguish right from wrong; or worst still, if he had no willpower to resist from doing wrong? The Prophet was to teach people the Book of Allah; this means that he KNEW the Commandment of Allah. He was to purify them and teach them wisdom. This means he himself had wisdom and purity.
Witness to the perfection of his character is found in Quran where Allah states:
"And most certainly you are on sublime morality (exalted standard of character)." (Quran 68:4)
A man committing mistakes does not deserve such compliments. All these verses clearly prove two things:
1. The authority of the Holy Prophet upon the believers was unlimited and all-comprehensive. Any order given by him, under any condition, in any place, at any time, was to be obeyed unconditionally.
2. Supreme authority was given to him because he was sinless (Ma'soom) and free from all types of errors and sins. Otherwise, Allah would not have ordered us to obey him with no questioning or doubt.