Musannaf Ibn Abi Shayba 3:3866

Abu Bakr narrated to us, he said: Hushaym narrated to us, he said: 'Awf informed us, he said: An agent of Mu'awiyah arrived, and he had sent him for the alms (sadaqat). He stopped at a place and found two mosques. He said: "Which of them is older?" He was informed about it, so he went to the one that was the older of the two.