Sayyida Umm Fadl (may Allah be pleased with her) narrates: A man came to the service of the Prophet (peace be upon him) and said: O Messenger of Allah (peace be upon him)! I have married a woman, and I already had a wife before. My first wife says that she has breastfed my new wife once or twice. The Prophet (peace be upon him) said: One or two sips do not establish prohibition.
Hadith Referenceصحیح ابن حبان / كتاب الرضاع / 4229
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح - «الإرواء» (2149): م.فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح على شرط مسلم