Ahmad ibn Muhammad from Ahmad ibn Abi Nasr from Hammad ibn Isa from Hariz ibn Abdullah from Zurarah, who said: I said to Abu Abdillah عليه السلام, peace be upon him: “A man doubts about the adhan while he has already entered into the iqamah.” Imam عليه السلام said: "He continues." I asked: “A man doubts about the adhan and the iqamah and he has already said the takbir.” Imam عليه السلام said: "He continues." I asked: “A man doubts about the takbir and he has already begun the recitation.” Imam عليه السلام said: "He continues." I asked: “He doubts about the recitation and he has already bowed.” Imam عليه السلام said: "He continues." I asked: “He doubts about the bowing and he has already prostrated.” Imam عليه السلام said: "He continues with his prayer." Then Imam عليه السلام said: "O Zurarah, when you have left something and moved on to something else, your doubt regarding the former is of no consequence."