Quran 33:5 — The Parties (Al-Ahzab)

You shall give your adopted children names that preserve their relationship to their genetic parents. This is more equitable in the sight of GOD. If you do not know their parents, then, as your brethren in religion, you shall treat them as members of your family. You do not commit a sin if you make a mistake in this respect; you are responsible for your purposeful intentions. GOD is Forgiver, Most Merciful.

[33:4] GOD did not give any man two hearts in his chest. Nor did He turn your wives whom you estrange (according to your custom) into your mothers.* Nor did He turn your adopted children into genetic offspring. All these are mere utterances that you have invented. GOD speaks the truth, and He guides in the (right) path.

[33:6] The prophet is closer to the believers than they are to each other, and his wives are like mothers to them. The relatives ought to take care of one another in accordance with GOD's scripture. Thus, the believers shall take care of their relatives who immigrate to them, provided they have taken care of their own families first. These are commandments of this scripture.