On the 17th of Rabi al-Awwal, 83 AH, the fifth Imam, Muhammad al-Baqir (peace be upon him), was blessed with the birth of his successor to the Imamate. Imam as-Sadiq was distinguished among his brothers for the appointment as the sixth Imam from his infancy, and even nonbelievers recognized him as the next Imam following his father. Mohammed Amin al-Baghdady, a man among the most prominent figures and belonging to a highly revered family, narrated several of the countless merits of the sixth Imam, "Only he of his brothers was the caliph of his father and his trustee of authority, many sciences have been reported on his authority, and he was an Imani in tradition. His good traits were many."
The fifth Imam declared Imam as-Sadiq to be the Imam after him and to assume leadership of the Ummah following the death of his father at the hands of the Umayyad caliph Hisham ibn Abdul Malik in 114 AH. During a gathering, Imam al-Baqir looked towards Imam as-Sadiq and said to his followers, "Do you see that man? He is one of those of whom God, the Mighty and High, said: 'We wish to grant a favor to those who have been oppressed in the land, and we will make them Imams and inheritors.'" (28:5)
Historian, Scientist, Chemist, Philosopher, and Mathematician
The knowledge and teachings of Imam as-Sadiq were beyond reproach and earned him visitors from all over the world seeking to benefit from him. The fifth and sixth Imams were aware that during their time as representatives of Allah in the world, there would be an influx of books by Greek and Egyptian philosophers into the Islamic world, and alarm was raised because many Muslims began accepting these works as truths. The intellectual awakening of the Muslim world during the second century was not due to foreign influences as many Western textbooks allude to; rather, it was a movement led by Imam Muhammad al-Baqir and his son Imam Jafar al-Sadiq.
The Imams dedicated themselves to ensuring Muslims were not entrapped by false knowledge that would imprison their minds for centuries with wrong and malicious information. The students of Ahlul Bayt were taught knowledge of the sciences, astronomy, and mathematics in addition to religious information so that they too could spread this information to Muslims. The efforts of the Ahlul Bayt resulted in one of the most monumental intellectual ages among Muslims that has yet to be reached again.
The intellectual contributions of Imam as-Sadiq were numerous and extensive in their respective disciplines. He was the first person in history to separate science from philosophy, arguing that they are two widely different fields. Prior to this point, philosophers were considered scientists, and scientists were philosophers. At the age of 11, the Imam refuted the Ptolemaic system and was the first to argue that the Earth was not the center of the universe, and the Sun did not rotate around the Earth. The Imam further argued that the Earth rotates on its axis. Unfortunately, these accomplishments are attributed to Copernicus and Galileo.
Imam as-Sadiq was a scholar of over two hundred disciplines ranging from mathematics to political science and founded the first university in the Islamic world. Modern scientists find agreement with many of the Imam's theories including those concerning the origin of the universe, physics, heat energy, and hydrogen. Among the students of Imam al-Sadiq were Jabir ibn Hayan (Father of Chemistry), Abu Hanifa (founder of the Hanafi school of thought), and Malik ibn Anas (founder of the Maliki school).
Pillar of Honor
Imam as-Sadiq's intellectual achievements could only be rivaled in excellence by his piety, worship, benevolence, and service to Islam. The Progeny of the Prophet (peace be upon him and his household) was characteristically similar to Prophet Ibrahim and would rarely have a meal without the destitute and poor as their guests. While the guests were treated to a plethora of food, Imam as-Sadiq's meal consisted of bread and vinegar. The Imam lived most of his blessed life in Medina, and at night time he would carry a sack of bread, meat, and Dirhams and distributed it secretly among the impoverished. The beneficiaries of the Imam's generosity and kindness did not know it was the Imam providing them with their sustenance until his death came and the gifts ceased to appear on their doorsteps.
The Imam's worship was exalted and astounding for many people to witness. It has been narrated that one day, Abu Hanifa saw him praying and was left perplexed by it. When the Imam completed the prayers, he said, "O Aba Abdillah! How torturous is your prayer!" Imam Sadiq replied, "Don't you know that among all the worship acts, prayer is the greatest cause of divine proximity?"
His prayers were extended and his supplications towards Allah were never rejected. A woman once came to the Imam and told him, "May I be your ransom, son of Allah's Apostle (may Allah bless him and his family), I have leprosy in my upper arm. Invoke Allah to heal me." The Imam then supplicated to Allah and said, "Allah, You heal the blind and the leprous and bring life to the decayed bones. Forgive her and heal her to see the effect of the acceptance of my supplication." The woman was cured of her illness immediately due to the high honor and rank of Imam as-Sadiq before Allah.
Traditions by the Sixth Imam
Below is an excerpt from the instructions given by Imam al-Sadiq to his successor and son, Imam Musa al-Kadhim (peace be upon them both):
"My son, accept my commandments and memorize my words, for if you memorize them, you will lead a happy (life) and die a praised (death). My son, indeed, whoever is content becomes rich, whoever looks at what is in the hand of other than him dies poor, whoever is displeased with what Allah has predestined for him accuses Allah in His Decree, whoever regards his own slip as small regards the slip of others as big. My son, whoever uncovers the veil of others, his defect is uncovered, whoever draws the sword of disobedience is killed with it, whoever digs a well for his brother falls into it, whoever makes friends with the foolish is degraded, whoever makes friends with the knowledgeable is respected, and whoever enters the evil places is accused. My son, say the truth for you or against you, and beware of slander, for it plants enmity in the hearts of men. My son, when you seek generosity, seek it from its places (i.e. the noble men), for generosity has places, the places have origins, the origins have branches, the branches have fruit, no fruit is sought but with a branch, and no firm origin but in a good place. My son, when visit, visit the good, but do not visit the wicked, for they are like the solid rock whose water does not gush out, the tree whose leaves do not get green, and the land whose plants do not appear."
Akhlaq e-A'imma: Morals & Manners of the Holy Imams by Sayyid Zafar Hasan Amrohi
Imam al-Sadiq by Shaikh Muhammad Hussain al-Mudhaffar
Kitab al-Irshad by Shaikh al-Mufid