When one of you makes supplication, he should supplicate with a will and should not say: O Allah, confer upon me if Thou likest, for there is none to coerce Allah.
When one of you makes a supplication (to his Lord) one should not say: O Allah, grant me pardon, if Thou so likest, but one should beg one's (Lord) with a will and full devotion, for there is nothing so great in the eye of Allah which He cannot grant.
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).
I visited Khabbab who had seven cauteries on his stomach and he said: Had Allah's Messenger (ﷺ) not forbidden us to call for death, I would have done so.
Abu Huraira narrated to us ahadith from Allah's Messenger (ﷺ) and out of these one is that Allah's Messenger (ﷺ) said: None amongst you should make a request for death, and do not call for it before it comes, for when any one of you dies, he ceases (to do good) deeds and the life of a believer is not prolonged but for goodness.