From Sahih Bukhari (Hadith 2961):
Narrated Anas:On the day (of the battle) of the Trench, the Ansar were saying, "We are those who have sworn allegiance to Muhammad for Jihad (for ever) as long as we live." The Prophet (ﷺ) replied to them, "O Allah! There is no life except the life of the Hereafter. So honor the Ansar and emigrants with Your Generosity
Reference: Bukhari 2961