Indeed, in this [Quran] is notification for a worshipping people. And We have not sent you, [O Muhammad (P.B.U.H)], except as a mercy to the worlds. (Quran: 21:106-107)
Allah's Messenger was the kindest of men in the same way as he excelled all others in courage and valour. Being extremely kind-hearted, his eyes brimmed with tears at the slightest sign of inhumanity. A Companion, Shaddaad bin 'Aws reported the Apostle as saying: "Allah has commanded you to show kindness to everyone, so if you have to kill, kill in a good manner, and if you slaughter an animal, slaughter it gently. If anyone of you has to slay an animal, he should sharpen the blade first and treat the animal well."