ما هو الدعاء أو الصلاة الموثوق به من القرآن أو السنة لتحقيق حاجة؟

One must believe that Allah answers the supplication of His servant if the conditions for acceptance are met and the impediments are removed. He either hastens the fulfillment of the supplication in this world, or stores it for him as good deeds in the Hereafter, or averts from him an equivalent amount of evil. The evidence for this is the Almighty’s saying: "And when My servants ask you concerning Me, then [answer them], I am indeed near. I respond to the invocation of the supplicant when he calls upon Me. So let them respond to Me [by obedience] and believe in Me that they may be rightly guided," and His saying: "And your Lord says, 'Call upon Me; I will respond to you.' " Among the conditions for acceptance is that the servant responds to Allah by obeying His commands and prohibitions, believes in His promise, and does not hasten the response. On the authority of Abu Hurayrah, the Prophet, peace and blessings be upon him, said: "The supplication of any one of you will be answered as long as he does not pray for a sin or the cutting off of ties of kinship, and as long as he is not impatient." Therefore, a Muslim should respond to Allah, trust in His promise, seek out times of acceptance, begin his supplication by praising Allah and invoking blessings upon the Prophet, peace and blessings be upon him, and conclude it likewise.