Musnad Abu Ya'la al-Mawsili 115:36

Hadbata narrated to us, Hammam narrated to us, Qatadah narrated to us, from Anas, that the Messenger of Allah (may Allah bless him and grant him peace) sacrificed two white-and-black horned rams. He placed his foot on their sides, then slaughtered them with his own hand, while mentioning the name of Allah and saying the Takbir.