Maliks Muwatta Book 54, Hadith Number 4.

Section : Blessing the Person who Sneezes.

Malik related to me from Abdullah ibn Abi Bakr from his father that the Messenger of Allah, may Allah bless him and grant him peace, said, “If a man sneezes, invoke a blessing on him. Then if he sneezes, invoke a blessing on him. Then if he sneezes, invoke a blessing on him. Then if he sneezes, say, ‘You have a cold’.” Abdullah ibn Abi Bakr said, “I don’t know whether it was after the third or fourth.”