In Ezekiel 36:33-38, the Word of God gives us a glimpse at the mystery of prayer:
 “Thus says the Lord GOD: On the day that I cleanse you from all your iniquities, I will cause the cities to be inhabited, and the waste places shall be rebuilt.  And the land that was desolate shall be tilled, instead of being the desolation that it was in the sight of all who passed by.  And they will say, ‘This land that was desolate has become like the garden of Eden, and the waste and desolate and ruined cities are now fortified and inhabited.’  Then the nations that are left all around you shall know that I am the LORD; I have rebuilt the ruined places and replanted that which was desolate. I am the LORD; I have spoken, and I will do it.
 “Thus says the Lord GOD: This also I will let the house of Israel ask me to do for them: to increase their people like a flock.  Like the flock for sacrifices, like the flock at Jerusalem during her appointed feasts, so shall the waste cities be filled with flocks of people. Then they will know that I am the LORD.”
The Lord God’s deliberate action to deliver his people in the latter days is clearly seen throughout these verses: “I cleanse… I will cause… I have rebuilt… I have spoken… I will do it… I will let…” This is the gracious, promise-keeping Lord God. He will keep his promises to the people of Israel. The sins of these redeemed saints are cleansed, verse 33 says. He will restore them both to himself and to the land. In fact, in the latter days the once-desolate land will become “like the Garden of Eden.” The people will be numerous again, inhabiting the land. The result of the Lord’s gracious actions is that the nations will know that he is the Lord, the one true God. We can be sure that the Lord will do this.
The Lord will use prayer as the means to accomplish this. “This also I will let the house of Israel ask me to do for them.” The object of the people’s prayers here is that re-population of redeemed people during this end-time restoration, when God will “increase their people like a flock.” The Lord does not fill the Promised Land with just any people, but people who truly and rightly worship the Lord. Moreover, these people are described as those who “will know that I am the Lord.” In sum, all that the Lord is so determined to do in verses 33-36 he is using prayer as a means to accomplish in verses 37-38.
Throughout Scripture, God uses prayer to accomplish what God has certainly determined in the good council of his will to do.
Prayer is not an exercise in informing God, either. Our Father knows what we need even before we ask him (Matt 6:8; cf. Psa 139:2; Isa 66:18). In fact, he knows better what we need than we do. Furthermore, God’s will does not change (1 Sam 15:29; Eph 1:4, 11). Our prayers, therefore, properly speaking, cannot change God’s knowledge or his will. God acts because of his own good pleasure, and it should be the prayer of all true believers that God would only act in this way. At the same time, God has established prayer, and graciously bids us come to him with our requests. He is a prayer-hearing God. As we can see in the passage from Ezekiel 36, God is pleased to move his people to pray as an antecedent to accomplishing his saving acts, and in such a way to show that his people’s prayers matter to him.
Even though God has purposed to use prayer to accomplish the good purpose of his will, and even though prayer does not increase God’s knowledge or change his will, it would be a mistake to conclude that prayer is any way meaningless, redundant, or even arbitrary. As Jonathan Edwards pointed out in his sermon, “The Most High a Prayer-Hearing God,” there are at least two great reasons that God has given prayer:
There may be two reasons given why God requires prayer in order to the bestowment of mercy; one especially respects God, and the other respects ourselves.
1. With respect to God, prayer is but a sensible acknowledgment of our dependence on him to his glory. As he hath made all things for his own glory, so he will be glorified and acknowledged by his creatures; and it is fit that he should require this of those who would be the subjects of his mercy. That we, when we desire to receive any mercy from him, should humbly supplicate the Divine Being for the bestowment of that mercy, is but a suitable acknowledgment of our dependence on the power and mercy of God for that which we need, and but a suitable honour paid to the great Author and Fountain of all good.
2. With respect to ourselves, God requires prayer of us in order to the bestowment of mercy, because it tends to prepare us for its reception. Fervent prayer many ways tends to prepare the heart. Hereby is excited a sense of our need, and of the value of the mercy which we seek, and at the same time earnest desires for it; whereby the mind is more prepared to prize it, to rejoice in it when bestowed, and to be thankful for it. Prayer, with suitable confession, may excite a sense of our unworthiness of the mercy we seek; and the placing of ourselves in the immediate presence of God, may make us sensible of his majesty, and in a sense fit to receive mercy of him. Our prayer to God may excite in us a suitable sense and consideration of our dependence on God for the mercy we ask, and a suitable exercise of faith in God’s sufficiency, that so we may be prepared to glorify his name when the mercy is received.
God hears our prayers. He answers our prayers. He has appointed prayer as one of the ways he accomplishes what he himself has promised to do. In this, God teaches us who take up prayer how much we need him and his grace. Through prayer we are also prepared to receive with thankfulness and praise the grace he gives us when he answers our prayers.