Hazrat Ata bin Yasar says that I asked Hazrat Abdullah bin Amr (may Allah be pleased with him) and Hazrat Ka'b that if a person is in doubt whether he has prayed three rak'ahs or four, what should he do? Both of them replied that he should pray one rak'ah, then sit at the end and perform sajdah sahw.

Ibrahim says that he will reflect and perform the prostration of forgetfulness (sujood as-sahw).

Hazrat Salim says that he will act upon what he is certain of. He was asked whether he will perform Sajdah Sahw? He replied, yes.

Hazrat Mak'hool narrates that the Messenger of Allah, peace and blessings be upon him, said: If any of you has doubt about his prayer as to how many rak'ahs he has performed, and if he is uncertain whether it was one or two rak'ahs, then he should perform one more rak'ah so that the doubt turns into excess. Then, while sitting in the position of Tashahhud, before saying the final salam, he should perform Sajdah Sahw, and then say the salam. Hazrat Kareeb says that regarding this hadith, Hazrat Umar and Hazrat Ibn Abbas, may Allah be pleased with them both, had a difference of opinion, so Hazrat Abdur Rahman bin Auf came and informed them that he had heard this hadith from the Messenger of Allah, peace and blessings be upon him.

Hazrat Abdul Kareem says that if Hazrat Saeed bin Musayyib and Hazrat Abu Ubaidah became doubtful about the number of units (rak‘ahs) in prayer and could not determine whether they had prayed three or four, both of them would perform the prostration of forgetfulness (sujood as-sahw) before concluding the prayer with salaam.

Hazrat Imran bin Husain narrates that the Holy Prophet Muhammad (peace and blessings be upon him) led us in the Asr prayer and after offering three rak‘ahs, he concluded the prayer with salam. Then he went to his chamber. A man, who was called Khirbaq, came forward and said, "O Messenger of Allah! You have done so today." Upon this, the Holy Prophet Muhammad (peace and blessings be upon him) came out angrily, dragging his cloak, and reached the people and asked, "Is what he says correct?" The people replied, "Yes." Upon this, he offered that rak‘ah, then concluded the prayer with salam, then performed two prostrations, and then again concluded with salam.

Hazrat Anas and Hasan say that he will act upon his last doubt and perform Sajdah Sahw.

Hazrat Ibn Umar (may Allah be pleased with them) said: Count as much as you are able, and do not repeat the prayer.

Hazrat Abdul Aziz bin Suhaib says that Hazrat Anas bin Malik (may Allah be pleased with him) sat for Tashahhud in the third rak'ah, so the people behind him said tasbih. He stood up and completed the fourth rak'ah. When he finished with salam, he performed two prostrations of forgetfulness (sujood as-sahw). Then, turning towards the people, he said: "When you are in doubt, do like this."

It is narrated from Hazrat Abu Huraira that the Messenger of Allah, peace and blessings be upon him, said: When you forget the amount of prayer, then while sitting in the position of Tashahhud, perform two prostrations of forgetfulness (sujood as-sahw).