Zayd bin Ishaq bin Jariyah al-Ansari (may Allah have mercy on him) says: When Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) brought the case of his child before Sayyiduna Abu Bakr (may Allah be pleased with him), he ruled in favour of the mother and then said: I heard the Messenger of Allah (peace and blessings be upon him) say: "Do not separate a child from its mother."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النفقات / 15767