Musannaf Ibn Abi Shayba 36:418

Abu Bakr narrated to us, he said: Sufyan ibn 'Uyaynah narrated to us, from 'Amr, from Abu al-'Abbas, from 'Abdullah ibn 'Amr—and once he said: from Ibn 'Umar—who said: The Messenger of Allah (may Allah bless him and grant him peace) besieged the people of Ta'if and did not attain anything from them. He said: "We are departing tomorrow." The Muslims said: "Shall we return and not have conquered it?" The Messenger of Allah (may Allah bless him and grant him peace) said: "Go forth to the battle." So they went forth, and wounds afflicted them. The Messenger of Allah (may Allah bless him and grant him peace) said: "We are departing tomorrow." That pleased them, so the Messenger of Allah (may Allah bless him and grant him peace) laughed.