The holy Imam Muhammad al-Baqir is the Fifth Apostolic Imam. His epithet was Abu Ja'far and he was popularly titled "al-Baqir". His mother was the daughter of Imam Hasan. Thus, he was the only Imam who was connected with Hadrat Fatimatu'z-Zahra', both from his paternal and maternal sides. Imam Muhammad al-Baqir was brought up in the holy lap of his grandfather Imam Husayn, for three years. For thirty-four years he was under the gracious patronage of his father, 'Ali Zaynu'l-'Abidin. The Holy Imam was present in Karbala' at the time of the gruesome tragedy of the wholesale massacre of his grandfather Imam Husayn and his companions. He also suffered with his father and the ladies of the House of the Prophet (Ahlu'l-Bayt) the heartless captivity and imprisonment at the hands of the devilish- forces at the command of Yazid ibn Mu'awiyah. After the tragedy of Karbala', the Imam passed his time peacefully in Medina praying to Allah and guiding the people to the right path.
The downfall of the Umayyads had begun since Yazid, the son of Mu'awiyah, had slaughtered Imam Husayn. Yazid himself had completely realized the evil consequences of his deeds even during the short period of his rule. His son Mu'awiyah, the second, refused to accept the caliphate saying: I cannot favour such a throne which has been erected on the basis of oppression and tyranny. Ibn Hajar al-Haytami, a famous scholar belonging to the Sunnite School says: "Imam Muhammad al-Baqir has disclosed the secrets of knowledge and wisdom and unfolded the principles of spiritual and religious guidance. Nobody can deny his exalted character, his God-given knowledge, his divinely-gifted wisdom and his obligation and gratitude towards spreading of knowledge.
He was a sacred and highly talented spiritual leader and for this reason he was popularly titled 'al-Baqir' which means 'the exponder of knowledge '. Kind of heart, spotless in character, sacred by soul and noble by nature, the Imam devoted all his time in submission to Allah (and in advocating the teachings of the Holy Prophet and his descendants). It is beyond the power of a man to count the deep impression of knowledge and guidance left by the Imam on the hearts of the faithful. His sayings in devotion and abstinence, in knowledge and wisdom, and in religious exercise and submission to Allah are so great in number that the volume of this book is quite in- sufficient to cover them all." (as-Sawa'iqu 'I-muhriqah, p. 120) The Holy Imam managed to collect the teachings and reforms of the Holy Prophet and his Ahlul-Bayt in the form of books. His pupils compiled books on different branches of science and arts under his instructions and guidance. In the excellence of his personal purity and godly traits, the Holy Imam Muhammad al-Baqir was a model of the Holy Prophet and his great grandfather, 'Ali ibn Abi Talib.
His admonitions created a spiritual sensation among the Muslims in general. He was not only hospitable even to his worst enemies but also used to continually exhort them to the right path. He urged people to earn their livelihood by their own hard work. The Holy Imam gave much importance to convening majalis (meetings) in commemoration of the martyrdom of Imam Husayn. Kumayt ibn Zayd al-Asadi, one of the most famous and highly talented poets of that time, used to recite the elegy of Imam Husayn in those majalis. Such type of majalis were also greatly encouraged by Imam Ja'far as-Sadiq and Imam 'Ali ar-Rida, the Sixth and the Eighth Imams. Imam Muhammad al-Baqir continued his preaching peacefully till 114AH. On the 7th Dhi'l-hijjah when he was fifty-seven years olds Hisham ibn 'Abdi 'I-Malik ibn Marwan, the then ruler, got him martyred through poison. The funeral prayers for this Holy Imam were conducted by his son Imam Ja'far as.-Sadiq, the Six Imam, and his body was laid to rest in Jannatu'l-Baqi' in Medina.

Allamah Tabatabai writes:
Imam Muhammad ibn 'Ali al-Baqir (the word 'Baqir meaning he who cuts and dissects, a title given to him by the Prophet) was the son of the Fourth Imam and was born in 57/675. He was present at the event of Karbala' when he was four years old. After his father, through Divine Command and the decree of those who went before him, he became Imam. In the year 114/732 he died, according to some Shiite traditions, he was poisoned by Ibrahim ibn al-Walid ibn 'Abdillah, the nephew of Hisham, the Umayyad caliph. During the Imamate of the Fifth Imam, as a result of the injustice of the Umayyads, revolts and wars broke out in some corner of the Islamic world every day.
More- over, there were disputes within the Umayyad family it- self which kept the caliphate busy and to a certain extent left the members of the Household of the Prophet alone. From the other side, the tragedy of Karbala' and the oppression suffered by the Household of the Prophet, of which the Fourth Imam was the most noteworthy embodiment, had attracted many Muslims to the Imam. These factors combined to make it possible for people and especially the Shi'ites to go in great numbers to Medina and to come into the presence of the Fifth Imam. Possibilities for disseminating the truth about Islam and the sciences of the Household of the Prophet, which had never existed for the Imams before him, were presented by the Fifth Imam.
The proof of this fact is the innumerable traditions recounted from the Fifth Imam and the large number of illustrious men of science and Shi`te scholars who were trained by him in different Islamic sciences. These names are listed in books of biographies of famous men in Islam. (Shi'ite Islam) Imam al-Baqir, peace be Upon him, said: The height of perfection is excellence in the understanding of the religion, endurance in hardships and administration of the affairs of life according to one's means, in the right measure. The scholar (`alim) who derives benefit from his knowledge is better than seventy thousand devotees ('abid ). One who disobeys Allah has no knowledge of Him.