From Sahih Muslim (Hadith 7072):
This hadith has been transmitted on the authority of Abdullah b. Mas'ud (who said):We were along with Allah's Messenger (ﷺ) at Mina, that moon was split up into two. One of its parts was behind the mountain and the other one was on this side of the mountain. Allah's Messenger (may peace be upbn him) said to us: Bear witness to this
Reference: Muslim 7072