Da'ud bin Abi Hnd داود بن أبي هند · The Book of ad-Dahaya (Sacrifices)

"I heard my father narrating from a man who said: 'We were with the Messenger of Allah two days before Al-Adha and we started to offer two Jadh ahs for one Thaniiyah, Then the Messenger of Allah said: 'A Jadh'ah is sufficient for that for which a Thaniyah is sufficient."

"There is no person who kills a small bird or anything larger, for no just reason, but Allah will ask him about it." It was said: "O Messenger of Allah, what does 'just reason mean?" He said: "That you slaughters it and eat it, and o not cut off its head and throw it aside,"