From Sahih Muslim (Hadith 7031):
Zaid b. Thabit reported that Allah's Apostle (ﷺ) set out for Uhud. Some of those persons who were with them came back. The Companions of Allah's Apostle (ﷺ) were divided in two groups. One group said:We would kill them, and the other one said: No, this should not be done, and it was on this occasion that this verse was revealed:" Why should you, then, be two parties in relation to hypocrites?" (iv)
Reference: Muslim 7031