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)
The chain is ordered from the source of the saying to the compiler: 1 = the speaker/first transmitter, the following links those who passed it on in turn, and at the bottom Muslim who compiled the work. Click a narrator to list every hadith in which he appears; the number in parentheses is how many hadiths across the collections on this site the narrator appears in.