Bismillah Walhamdulillah Was Salaatu Was Salaam ‘ala Rasulillah
Narrated Anas bin Malik (Radi-Allahu ‘anhu):
Two men sneezed before the Prophet (Sallallahu ‘Alaihi Wa Sallam). The Prophet (Sallallahu ‘Alaihi Wa Sallam) said to one of them, “May Allah bestow His Mercy on you,” but he did not say that to the other. On being asked (why), the Prophet (Sallallahu ‘Alaihi Wa Sallam) said, “That one praised Allah (at the time of sneezing), while the other did not praise Allah.”
Bukhari Vol. 8 : No. 240