Musnad Ahmad 30:1175

'Affan narrated to us, Hammam narrated to us, Qatadah informed us, from 'Abd al-Malik, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Whoever is offered something without having asked for it, let him accept it, for it is only a provision that Allah has driven to him."