Musnad Ahmad 579:1

'Abdullah ibn Yazid narrated to us, Sa'id ibn Abi Ayyub narrated to us, Abu al-Aswad narrated to me, from Bukayr ibn 'Abdullah, from Busr ibn Sa'id, from Khalid ibn 'Adi al-Juhani, who said: I heard the Messenger of Allah (peace and blessings of Allah be upon him) saying: "Whoever receives a kindness from his brother without asking for it, and without his soul coveting it, let him accept it and not reject it, for it is only a provision that Allah has driven to him."