What is the ruling on prayers in which one laughed without a sound or with a breath-like sound, and it is not known whether two letters appeared or not? And must they be made up, given that their number and type are not remembered? And what is the ruling on one who laughed during the prostration of forgetfulness after the taslim?

The majority of scholars agree that laughing aloud with the emission of two or more letters invalidates the prayer. However, smiling without a sound does not invalidate the prayer and does not require its re-performance. Al-Nawawi and Ibn Al-Mundhir reported the consensus of scholars that prayer is invalidated by laughter from which two letters are clearly audible. Most scholars hold that smiling is permissible. Prayer is invalidated by a loud guffaw, whether intentional or accidental, because it involves the contraction of the lips with sound, whereas smiling is the relaxation of the face without sound and does not necessitate prostration, although intentional smiling is disliked. The ruling for laughing during the prostration of forgetfulness is the same as its ruling during the prayer itself: if it is a guffaw or if two or more letters are audible, the prayer is invalidated; otherwise, it is not. A Muslim should be humble in their prayer and distance themselves from distractions that cause laughter or smiling.