Musnad Ahmad 28:609

Abu Sa’id, the freed slave of Banu Hashim, narrated to us, Muhammad ibn Rashid narrated to us, Sulayman ibn Musa narrated to us, from ‘Amr ibn Shu’ayb, from his father, from his grandfather, that the Messenger of Allah (may Allah bless him and grant him peace) said: "The blood money for quasi-intentional homicide is aggravated, like the blood money for intentional homicide, but its perpetrator is not to be killed. And whoever bears arms against us is not one of us, and [whoever] lies in wait on the road [is not one of us]."