Musnad Ahmad 992:0

Narrated Muhammad ibn Abdullah ibn Jahsh: A man came to the Messenger of Allah (ﷺ) and asked, "O Messenger of Allah, what do I get if I am killed in the way of Allah?" The Messenger of Allah (ﷺ) said, "Paradise." When the man turned to leave, the Messenger of Allah (ﷺ) called him back and said, "Paradise, unless it be a debt; Jibril whispered that to me just now."