Musannaf Ibn Abi Shayba 19:234

Abu Bakr narrated to us, he said: Yazid bin Harun narrated to us, he said: Ibn Abi Dhi'b informed us, from al-Zuhri, from Tariq al-Shami, that a man was brought to him for theft, so he struck him, and he confessed. He then sent to Ibn Umar to ask him about that. Ibn Umar said to him: "Do not cut him, for he only confessed after you struck him."