بُلُوغُ الْمَرَامِ
Bulugh al-Maram 1128
Marriage
وَعَنْهَا قَالَتْ: قَالَ رَسُولُ اَللَّهِ - صلى الله عليه وسلم -{ اُنْظُرْنَ مَنْ إِخْوَانُكُنَّ, فَإِنَّمَا اَلرَّضَاعَةُ مِنْ اَلْمَجَاعَةِ. } مُتَّفَقٌ عَلَيْهِ [1] .
Narrated ['Aishah (RA)]: Allah's Messenger (ﷺ) said: "Be sure (you women) who your brothers are, for suckling is that which is the result of hunger (i.e. when milk is the child's only food)." [Agreed upon].
Sunnah.com reference: Book 8, Hadith 192