Musnad Ahmad 5:602

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from ‘Asim ibn Kulayb, he said: I heard Abu Burdah, he said: I heard ‘Ali ibn Abi Talib, he said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Say: O Allah, I ask You for guidance and rectitude (sadad). And remember by guidance your guidance of the path, and remember by rectitude your straightening of the arrow." He said: "And he forbade—or he forbade me—from [using] qasi (bows/saddles), and the mitharah (silk saddle cushion), and from the ring on the index finger or the middle finger."