The Cow - 2:220
"About this world and the Hereafter And they ask you about orphans: Say, "It is the greatest good if you bring them up as righteous people. If you add their property to your property, they will become members of your family."Allah knows how to distinguish the corrupt from the righteous. Had Allah willed, He could have made you hardship. Allah is Mighty, Wise."
When orphans become family members:
The Coalition/33:4
Allah has not put two hearts in any man. He has not made your wives your mothers, whom you forbade yourselves by likening them to your mothers, nor has He made your adopted children your own children. All this is but the words of your mouths. Allah speaks the truth and He guides.
The Coalition/33:5
Call them in a way that does not cut them off from their natural fathers. This is more right in the sight of Allah. If you do not know their fathers, then they are your brothers in religion and members of your family. There is no responsibility on you for what you do by mistake, except what you do intentionally. Allah is Forgiving, Merciful.