Allah has prescribed Du`a' and ordered people to observe it
Allah, Exalted be He, has ordained Du‘a’ and He commands us to call upon Him, saying (what means):
And your Lord said: “Invoke Me, I will respond to your (invocation).
(Surah Ghafir, 40: 60). He also says (what means):
And when My slaves ask you (O Muhammad صلى الله عليه وسلم) concerning Me, then (answer them), I am indeed near (to them by My Knowledge). I respond to the invocations of the supplicant when he calls on Me (without any mediator or intercessor).
(Surah Al-Baqarah, 2: 186). If a servant of Allah acts according to the ordained means and supplicates to Allah, this is considered part of the Divine Decree. So, it is averting a Divine Decree by Divine Will and Decree. It is authentically established that the Messenger of Allah (peace be upon him) said in a Sahih (authentic) Hadith:
“A man is deprived of provision because of a sin that he commits; and nothing can avert predestination except Du‘a’ (supplication) and nothing increases lifespan except righteousness.”
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.