Musannaf Ibn Abi Shayba 28:724

Hafs ibn Ghiyath narrated to us, from Hajjaj, from al-Hakam, from Miqsam, from Ibn Abbas, who said: The Messenger of Allah (may Allah bless him and grant him peace) wrote a document between the Emigrants (Muhajirun) and the Helpers (Ansar) that they should pay their blood-monies (ma'aqil) and ransom their captives (ani) with kindness and reconciliation among the Muslims.