Musnad Ahmad 551:2

Waki’ narrated to us, Musa ibn ‘Ali ibn Rabah—that Lakhmite—narrated to us, from his father, who said: I heard ‘Amr ibn al-‘As saying: The Messenger of Allah (ﷺ) said to me: "O ‘Amr, fasten your weapon and your clothes upon you, and come to me." So I did, and I came to him while he was performing ablution. He looked at me, up and down, and said: "O ‘Amr, I intend to send you on an expedition, so Allah will keep you safe and grant you spoils, and I will set aside for you a good portion of wealth." I said: "O Messenger of Allah, I did not embrace Islam out of a desire for wealth; rather, I embraced Islam out of a desire for Jihad and to be with you." He said: "O ‘Amr, how excellent is righteous wealth for a righteous man."