Musannaf Ibn Abi Shayba 13:710

Abu Bakr narrated to us, he said: Isma'il ibn Ibrahim—who is Ibn 'Ulayyah—narrated to us, from Yahya ibn Yazid al-Huna'i, he said: I asked Anas ibn Malik about a man whose debtor gives him a gift. He said: "If he used to give him gifts before that, then there is no harm. But if he did not use to give him gifts before that, then it is not proper."