General Behavior (Kitab Al-Adab)

Dawud :: Book 41 : Hadith 5018

Narrated Ubayd ibn Rifa'ah az-Zuraqi:

The Prophet (peace_be_upon_him) said: Invoke a blessing on one who sneezes three times; (and if he sneezes more often), then if you wish to invoke a blessing on him, you may invoke, and if you wish (to stop), then stop.