Ayesha reported,

Abu Huzaifa adopted Salim, who was the freed slave of a woman from the Ansar, just as the Prophet ﷺ had adopted Zayd. In the time of ignorance, when a man adopted another, people would call the adopted one his son and he would inherit from his estate, until Allah revealed, "Call them by the names of their fathers. That is more just in the sight of Allah. But if you do not know their fathers, then they are your brothers in religion and your freed companions" [Ahzab 33:5]. So they were attributed back to their fathers, and whoever's father was unknown became a mawla and a brother in religion.Then Sahla came and said, "Messenger of Allah, we used to regard Salim as a son. He would stay with me and with Abu Huzaifa, and he would see me in my house clothes. Now Allah has revealed concerning them what you know."He replied, "Nurse him five times, and he will become like your son through nursing."

حدثنا عبد الرزاق قال أخبرنا ابن جريج قال أخبرنا ابن شهاب أخبرني عروة بن الزبير

عن عائشة

أن أبا حذيفة تبنى سالما وهو مولى لامرأة من الأنصار كما تبنى النبي ﷺ زيدا وكان من تبنى رجلا في الجاهلية دعاه الناس ابنه وورث من ميراثه حتى أنزل الله عز وجل {ادعوهم لآبائهم هو أقسط عند الله فإن لم تعلموا آباءهم فإخوانكم في الدين ومواليكم} فردوا إلى آبائهم فمن لم يعلم له أب فمولى وأخ في الدين فجاءت سهلة فقالت يا رسول الله كنا نرى سالما ولدا يأوي معي ومع أبي حذيفة ويراني فضلا وقد أنزل الله عز وجل فيهم ما قد علمت فقال أرضعيه خمس رضعات فكان بمنزلة ولده من الرضاعة