A Treatise on the Prostration of Forgetfulness
All praise is due to Allah, the Lord of the worlds. May Allah's peace and blessings be upon our Prophet Muhammad, who conveyed the message clearly and perfectly, and upon his family, his Companions, and those who followed them in the best way until the Day of Judgment.
To proceed, Many people are ignorant of the rulings of the prostration of forgetfulness which is to be offered when an incident of forgetfulness occurs during prayer. Some people fail to offer such prostration when it is due, some offer it when it is not due, some offer it before Taslīm (concluding the prayer with Salām) when it should be offered after it, and others offer it after Taslīm when it should be offered before it. Therefore, knowing its rulings is a matter of great importance, especially by those who lead people in prayer and shoulder the responsibility of following the guidance prescribed by the shariah in their prayer in which they lead other Muslims.
This urged me to present to my fellow Muslims some of the rulings related to this topic, hoping that Allah Almighty would benefit with it His believing servants.
The prostration of forgetfulness consists of two prostrations which one has to offer to make up for a shortcoming that has occurred in his prayer out of forgetfulness.
It is due in three cases: adding something to the prayer, leaving something of it, or harboring doubt about its perfection.
If the praying person adds an action to his prayer like standing, sitting, bowing, or prostrating deliberately, then his prayer is invalid. If, however, he does so out of forgetfulness and he did not remember the addition until he finished it, then he is only required to offer the prostration of forgetfulness, and his prayer is valid. But if he becomes aware that he is making an addition while making it, then he has to stop it immediately and the prostration of forgetfulness becomes due on him, and his prayer is valid.
Example: Someone performed the Zhuhr prayer five rak‘ahs without remembering that extra rak‘ah until he comes to recite the Tashahhud. In this case, he has to complete the Tashahhud, make Taslīm, then offer the prostration of forgetfulness, then make Taslīm again. If he fails to remember the addition he made until he makes Taslīm, he should offer the prostration of forgetfulness then make Taslīm again. If he remembers the addition when he is offering the fifth rak‘ah, he should sit down immediately, recite Tashahhud, make Taslīm, then offer the prostration of forgetfulness then make Taslīm.
The Hadīth of ‘Abdullah ibn Mas‘ūd (may Allah be pleased with him) wherein he reported: "The Prophet (may Allah's peace and blessings be upon him) once prayed Zhuhr five rak‘ahs. So, someone said: 'Has increase been made in the prayer?' He replied: 'Why do you say that?' They said: 'You have prayed five (rak‘ahs).' So he performed two prostrations after having made Taslīm." According to another version: "… so he turned his feet and faced the Qiblah, and he performed two prostrations then made Taslīm."
Making Taslīm before completing the prayer is a form of addition in the prayer [1]. So if the praying person makes Taslīm before completing the prayer deliberately, then his prayer is invalid.
[1] It is a form of addition because an extra act of Taslīm is added to the prayer while still performing it.
If he did that out of forgetfulness and a long time passes before he remembers, then it is due upon him to perform the prayer anew.
But if he remembers after a short while, such as two or three minutes, then he should complete his prayer and make Taslīm, then he should offer the prostration of forgetfulness and make Taslīm.
The Hadīth of Abu Hurayrah (may Allah be pleased with him) wherein he reported that the Prophet (may Allah's peace and blessings be upon him) led them in Zhuhr or ‘Asr prayer and made Taslīm after two rak‘ahs. So the people rushed out of the mosque doors asking each other: "Has the prayer been shortened?" The Prophet (may Allah's peace and blessings be upon him) got up toward the wooden beam of the mosque and leaned against it as if he was angry. A man stood up and said: "O Messenger of Allah, have you forgotten or has the prayer been shortened?" He replied: "Neither have I forgotten nor has it been shortened." A man said: "Surely, you have forgotten." The Prophet (may Allah's peace and blessings be upon him) asked the Companions: "Is what he is saying true?" They said: "Yes, it is." So he moved forward and offered the remaining two rak‘ahs of his prayer then made Taslīm, then he performed two prostrations (of forgetfulness) then made Taslīm."
If the imam makes Taslīm before completing the prayer and there are among those led in prayer some who have missed part of the prayer, so they get up to make up for what they have missed and then the imam remembers that he has left something of the prayer and gets up to complete it; in this case, those who got up to make up for what they had missed have the choice either to go on making up for the missed part then offer the prostration of forgetfulness, or go back to following the imam and when he finishes they make up for the missed parts then offer the prostration of forgetfulness after making Taslīm. This last choice is more proper and cautious.
If the praying person leaves out a pillar of the prayer; if it is the Opening Takbīr, then his prayer is annulled whether he leaves it deliberately or forgetfully, because his prayer has not validly started in the first place.
If he leaves a pillar other than the Opening Takbīr, his prayer is invalid if he does that deliberately.
But if he leaves it forgetfully; and he reaches its point in the second rak‘ah, the preceding rak‘ah is annulled and the following rak‘ah replaces it. If he has not yet reached its point in the second rak‘ah, he must go back and perform the forgotten pillar and the actions that come after it. In both cases he has to perform the prostration of forgetfulness after making Taslīm.
Example: someone forgot to perform the second prostration of the first rak‘ah, and he only remembered that when he was sitting between the two prostrations of the second rak‘ah. In this case, the first rak‘ah is annulled and the second replaces it. He should consider the second rak‘ah as the first, complete his prayer based upon this and make Taslīm. Then he performs the prostration of forgetfulness and makes Taslīm.
Another example: someone forgot the second prostration and the sitting that precedes it of the first rak‘ah. He remembered that after he rose from bowing in the second rak‘ah. In this case, he has to go back and sit down and perform that second prostration then complete his prayer and make Taslīm. Then, he performs the prostration of forgetfulness and makes Taslīm.
If he does so out of forgetfulness but he remembers before he moves on from its place in the prayer, he has to perform it and he does not have to do anything more. If he remembers it after having moved on from its place in the prayer but before reaching the next pillar, then he should go back and perform it. Then he completes his prayer and makes Taslīm, prostrates for forgetfulness and makes Taslīm.