Musannaf Ibn Abi Shayba 13:1586

Abu Bakr narrated to us, he said: Ibn ‘Ulayyah narrated to us, from Yunus, from al-Hasan, who said: A *mukātab* (a slave under a contract of manumission) asked for [help with] one neck or two necks, so he was given a gift. When what was given to him seemed excessive in the eyes of Abu Musa, he ordered it and what had been given to be brought in. Then he looked at that which he had asked for, and he gave it to him. He then took the surplus and placed it toward his neck or [the] necks.