Sunan Ibn Majah
3714
Sahih+2

It was narrated from Ilyas bin Salamah bin Akwa' that his father said:"The Messenger of Allah(ﷺ) said: 'The one who sneezes may be responded to three times; if he sneezes more than that, he has a cold

SahihAl-Albani
SahihMuhammad Fouad Abd al-Baqi