Makhool (may Allah have mercy on him) says that the Messenger of Allah (peace and blessings be upon him) said: "If any of you has doubt in prayer and does not remember whether he has prayed one rak'ah or two, then he should count it as one rak'ah. If he is in doubt between two and three, then he should consider them as two. If he is in doubt between three and four, then he should count them as three. After that, upon completing the prayer and before saying salam, he should perform two prostrations of forgetfulness (sujood as-sahw)."

Then, Husain bin Abdullah narrated this ruling with his chain and said: It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that once Sayyiduna Umar Farooq (may Allah be pleased with him) asked him, "O boy! Have you heard this issue from the Prophet (peace and blessings be upon him) or from any companion, that if a person has doubt in prayer, what should he do?" While this conversation was taking place, Sayyiduna Abdur Rahman bin Awf (may Allah be pleased with him) was seen coming from the front. He asked, "What are you discussing?" Sayyiduna Umar (may Allah be pleased with him) said, "I was asking this boy whether he has heard from the Prophet (peace and blessings be upon him) or from any companion about this issue, that if a person has doubt in prayer, what should he do?"