It is narrated from Sayyiduna Ibn Amr, may Allah be pleased with him, that the Noble Prophet, peace and blessings be upon him, said: "When children reach the age of seven, command them to pray; and when they reach the age of ten, punish them if they neglect the prayer, and separate their sleeping beds. And when any one of you marries off his slave or servant, he must never look at his private parts, for the area between the navel and the knees is 'awrah (private)."