The Position of the Prostration for Forgetfulness: Before or After the Closing Salam

Question:
The questioner: Honorable Shaykh, may Allah grant you success, is it permissible to always perform the prostration for forgetfulness before the closing salam?

Answer:
The Shaykh: It is permissible to perform the prostration for forgetfulness before the closing salam, and it is permissible to perform it after. However, the better option is that if the prostration for forgetfulness is due to a deficiency in the prayer, it should be performed before the closing salam; this is the better option because it serves as a completion of the prayer. If the prostration for forgetfulness is due to an addition, the better option is to perform it after the closing salam, because the prayer is complete and does not need completion; rather, it is to mislead Satan, so it is performed after the closing salam. But if a servant of Allah who performs it after the salam performs it before, or one who performs it before performs it after, that is somewhat incorrect. It is permissible to perform it before the salam in all cases, or after the salam in all cases. The distinction lies only in what is better.