Shaddad bin Aws (may Allah be pleased with him) says that I memorised two traits from the Prophet (peace and blessings be upon him): "Allah, the Lord of Might, has prescribed excellence (ihsan) in everything. When you kill or slaughter, do it in the best manner, and sharpen your knife, so that the animal being slaughtered may be given ease."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19137