Musnad Abu Ya'la al-Mawsili 108:12

'Abd al-A'la narrated to us, Hammad narrated to us, from Abu al-Zubayr, from Jabir: That a man slaughtered a young goat (atud) before the Prophet, may Allah bless him and grant him peace, prayed. The Prophet, may Allah bless him and grant him peace, said: "It shall not suffice for anyone after you to slaughter until he prays."