Musannaf Ibn Abi Shayba 21:43

Ibn Idris narrated to us, from Ibn ‘Ajlan, from Abu al-Zinad, from al-A‘raj, from Abu Hurayrah, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Let not one of you say, 'O Allah, forgive me if You will.' Rather, let him be firm in his request, for there is no one who can compel Him."