The worship of Imam Muhammad Taqi (a.s) was such that not a moment was without remembrance of Allah. Once he went for the Hajj. Seeing the intensive worship of the Imam, the pilgrims were left bewildered. Mutasim had also come for Hajj at that time. His officials reported to him the account of the worship of Imam Muhammad Taqi (a.s) and his sincerity and humility in prayers. They said, “We have never seen a more pious person.” The Imam used to weep the whole night in Allah’s remembrance and when people restrained him he intensified his lamentations and said, “When have I worshipped the Almighty as befits Him, that you ask me to reduce it?”
A significant proof of his excessive worship is that his wife Ummul Fadl the daughter of Caliph Mamun wrote in a complain letter to her father: You have married me to a person who spends the whole night standing in the prayer niche, and fasts during the day. Neither is he fond of beauty and embellishments nor there is any means of comfort and luxury in his house. Daughters of the kings cannot spend their life with such ascetics.
Reference :Akhlaq al-A’imma, Morals & Manners of the Holy Imams