Musnad Abu Ya'la al-Mawsili 243:30

Abu Bakr ibn Abi Shaybah narrated to us, Ubayd Allah ibn Musa narrated to us, from Ibrahim ibn Isma'il, from Taliq ibn Imran ibn Husayn, from Abu Burdah, from Abu Musa, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Allah has cursed the one who separates a parent from their child, and the one who separates a brother from his brother."