From Sahih Muslim (Hadith 6813):
Abu Huraira reported Allah's Messenger (ﷺ) as saying:None of you should say to Allah (like this): O Allah, grant me mercy, if thou so likest. The supplication (of his) should (be permeated with) conviction (that it would be accepted by the Lord), for Allah is the Doer of (everything) He likes to do, and there is none to force Him (to do or not to do this or that)
Reference: Muslim 6813