Ayesha reported,

The Messenger of Allah ﷺ came in to see me while a man was sitting with me. This troubled him deeply, and I saw anger in his face.I said, "Messenger of Allah, he is my brother through breastfeeding."He said, "Be careful about whom you consider your brothers through breastfeeding, for breastfeeding only counts when it is from hunger."

Azami 6691

Sahih

عن عائشة قالت

دخل علي رسول الله ﷺ وعندي رجل قاعد، فاشتد ذلك عليه، ورأيت الغضب في وجهه، قالت: فقلت: يا رسول الله، إنه أخي من الرضاعة قالت: فقال: انظرن إخوتكن من الرضاعة، فإنما الرضاعة من المجاعة.

الأعظمي 6691صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Breastfeeding
Section
Prohibited nursing is five sucklings for a young child under two years of age
Numbering
Jami al-Kamil 6691 (2nd edition)
Azami 6691