Hadith.1207 - Abu Basir narrated from Imam Jafar ibn Muhammad Al-Sadiq عليه السلام that when he asked: "Does the Imam guarantee (the correctness of) the prayer?"
Imam عليه السلام replied: "No, he is not a guarantor."
This is not contradictory to the narrations of Ammar and Imam Al-Ridha عليه السلام because the Imam is a guarantor for the prayer of those who pray behind him when they forget something, except for the opening takbir. He is not a guarantor for what the follower intentionally leaves out.
Another interpretation is that the Imam is not obligated to guarantee the completion of the prayer for the congregation because it is possible that something may occur to him before completing it, such as an event requiring him to break his prayer or realizing that he is not in a state of purity.
