Salim bin Abdullah narrates from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that a slave woman and her child are not to be separated in a division (of property). Salim bin Abdullah said: Even if the division does not come out equal? Abdullah (may Allah be pleased with them both) said: Even if the division does not come out equal.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18315