the benefit of supplication 

   

  Allah the Exalted says: and when My servant ask you O Muhammad concerning Me, indeed I   respond to the invocation of the supplication when he calls upon Me, so they should respond to ME, and believe in Me that they may be rightly guided (Albaqarah:186).

 This verse was revealed when a visitor from a village asked the Holy Prophet peace be upon Him: tell me if our lord is near us, then we shall pray (supplicate) in a lowered voice; and if He is far, we shall call Him with raised voices, there upon Allah said to His Messenger: I am near.

 Also Allah says I am as my servant thinks of Me, and I am with him whenever he invokes Me, and our prophet said that the supplication is worship, then He recite: "and your lord said call upon Me, I will respond to you verily those who scorn My worship, they will surely enter hell humiliated. 

 The supplication should be made slowly and quietly, and we should call upon Allah with fair of his displeasure and with hope of his mercy.

   

 There is three persons will not have their supplication rejected as Abu Hurayrah narrated from our Prophet Muhammad peace be upon Him, the first one is the just ruler, the second is the fasting person until breaking his fast, and the third is the supplication of the oppressed person, where the doors of the heaven opened for the supplication of the oppressed person, and Allah, Almighty, says to it: By my Grace! I will certainly grant it for you, even if after a while.