Musnad Ahmad 612:5

Abu Mu’awiyah narrated to us, al-A’mash narrated to us, from ‘Amr ibn Murrah, from Salim ibn Abi al-Ja’d, from Shurahbil ibn al-Simt, who said to Ka’b ibn Murrah: “O Ka’b ibn Murrah, narrate to us from the Messenger of Allah, may Allah bless him and grant him peace, and be cautious.” He said: “I heard the Messenger of Allah, may Allah bless him and grant him peace, say: ‘Shoot at the people of San’a. Whoever reaches the enemy with an arrow, Allah will raise him a degree because of it.’” He said: Then ‘Abd al-Rahman ibn Abi al-Nuham said: “O Messenger of Allah, and what is the degree?” The Messenger of Allah, may Allah bless him and grant him peace, said: “As for it, it is not the threshold of your mother, but between the two degrees is one hundred years.”