Bismillah Walhamdulillah Was Salaatu Was Salaam ‘ala Rasulillah
Narrated Abu Huraira (Radi-Allahu ‘anhu):
The Prophet (Sallallahu ‘Alaihi Wa Sallam) said, “Allah likes sneezing
and dislikes yawning, so if someone sneezes and then praises Allah, then
it is obligatory on every Muslim who heard him, to say: May Allah be
merciful to you (Yar-hamuka-l-lah). But as regards yawning, it is from
Satan, so one must try one’s best to stop it, if one says ‘Ha’ when
yawning, Satan will laugh at him.”
Bukhari Vol. 8 : No. 242