It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Among the gravest sins with Allah is (the sin of) a man who marries a woman, and when he has fulfilled his need from her, divorces her and takes away her dowry; and a man who hires someone and withholds his wages; and a man who kills an animal merely for sport, without reason." This hadith is sahih (authentic) on the condition of Imam Bukhari, but the two Shaykhs (Bukhari and Muslim) did not record it.