Amr bin Shu'ayb narrates from his father, and he from his grandfather (may Allah be pleased with him), that the Messenger of Allah (peace and blessings be upon him) said: "Command your children to pray at the age of seven, punish them for not praying at the age of ten, and separate their beds. And when one of you marries off his slave, his slave-girl or his hired worker, then let the slave-girl never look at any of his awrah, for from the navel to the knees is awrah."
It has also been narrated from Sawwar, from Muhammad bin Juhadah, from Amr, but that is of no worth.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3234