Quran 33.6-7
The Prophet is closer to the believers than their selves, and his wives are (as) their mothers. And the owners of kinship are closer one to another in the ordinance of Allah than (other) believers and the fugitives (who fled from Mecca), except that ye should do kindness to your friends. This is written in the Book (of nature). And when We exacted a covenant from the prophets, and from thee (O Muhammad) and from Noah and Abraham and Moses and Jesus son of Mary. We took from them a solemn covenant;