Fiqh-us-Sunnah - 2.47

Hadith 2.47.1

When to perform these prostrations

The "sujjud us-sahu" are to be performed in the following circumstances: If a person makes the taslim before he actually completes the prayers. Ibn Sireen relates from Abu Hurairah who said: "The Prophet sallallahu alehi wasallam prayed either zuhr or 'asr salah with us and he prayed only two rak'at and made the taslim. He got up and leaned against a piece of wood in the mosque as if he was angry. He put his right hand on his left and interlocked his fingers. Then, he placed his cheek on the back of his left hand. And some people left the mosque in a hurry. And they said: 'The prayer has been shortened?' Among the people were Abu Bakr and 'Umar, and they were shy to speak to him. One of the people, who was called Dhul-Yadain, said: 'O Messenger of Allah have you forgotten or has the prayer been shortened?' He answered: 'I have not forgotten and it has not been shortened.' Then he asked: 'Is it as Dhul-Yadain has said?' The people answered in the affirmative...At that, he led the people in what he had ommitted and made the taslim. After which he made the takbir and prostrated the way he usually prostrated or perhaps even longer. Next, he raised his head and made the takbir. Then, he made the takbir [again] and prostrated, like one of his customary sujjud or perhaps even longer, and finally, he raised his head." This is related by al-Bukhari and Muslim.
'Ata' relates that Ibn az-Zubair prayed maghrib and made the taslim after two rak'at and then he stood up and wanted to kiss the black stone, when the people tried to correct him he said: "What is the matter with you?" Then he prayed what he had left out and performed two sujjud.
When this was mentioned to Ibn 'Abbas, he said that it was not far from the sunnah of the Prophet sallallahu alehi wasallam. This is related by Ahmad, al-Bazzar, and at-Tabarani.
In one narration, it is stated: "Whoever prays and has some doubt that he was short of the complete prayer, he should continue praying until he suspects that he has added something to the prayer [with respect to the number of rak'at that he has prayed]." Abu Sa'id al-Khudri narrated that the Prophet sallallahu alehi wasallam said: "If one of you has some doubts during his prayer and does not know if he prayed three or four [rak'at], then he should remove his doubt by praying according to the amount that he is certain he had performed and then make two sujjud before the taslim. If he had prayed five rak'at, the two sujjud would make it even. If he had prayed a complete four rak'at [when he had finished], they would be in defiance of the Satan." This is related by Ahmad and Muslim. These two ahadith prove what the majority of the scholars have said, namely, if one has some doubt concerning the number of rak'at one has prayed, one should act according to the amount that one is certain to have prayed (the lesser amount) and then make two sujjud before the taslim.