"Lawful to you, [O Muhammad], are [not] these women, nor [is it for you] to take other wives in exchange for them," meaning: his nine wives. Al-Hasan said: When the Messenger of Allah (peace and blessings of Allah be upon him) gave his wives a choice, and they chose Allah and His Messenger, He restricted him to them. "Even if their beauty were to please you," meaning: the beauty of women other than those whom Allah has made lawful for him, based on the previous interpretation of Al-Hasan. "Except what your right hand possesses," he may have sexual relations with his slave girls as he wishes. "And Allah is ever, over all things, an Observer," meaning: a Protector.

Surat Al-Ahzab from (verse 53-55).