مسند أحمد

It was narrated from `Abeedah that ‘Ali (رضي الله عنه) mentioned the Khawarij and said: Among them is a man with a defective arm, or an incomplete arm, or a small arm. If you could exercise restraint, I would have told you what Allah promised on the lips of Muhammad (ﷺ) to those who kill them. I said: Did you hear that from Muhammad (ﷺ)? He said: Yes, by the Lord of the Ka`bah; yes, by the Lord of the Ka`bah; yes, by the Lord of the Ka`bah.