In our last post on Letters to Malcom we noted the questions asked of Lewis and then tooked into the Hebrew root of the word 'pray'. We saw that the reflexive conjugation of the verb means that whatever is done via prayer is done to oneself, and that the thing that is done is judgment or belief. This helps us address the first question. Lewis is asked how come so much of prayer seems to be telling things to God. But God is omniscient, he doesn't need to be told?
The answer, of course, is that by explicity stating these things while standing in God's presence (though He is everywhere, during prayer we are aware that we are standing in His presence), changes us. Us, not God. In prayer we see ourselves as we truly are, powerless, weak, controlled by outside forces, and perhaps, not trusing in Him. We lay that weakness in front to God and say, we've judged ourselves and now understand Who is really running to world, Who guides our lives, and Whose will we must follow. And we believe in Him, and perhaps that enables us to believe in ourselves. We have changed and, therefore, our lot in life can change as well.
Lewis says somewhat similarly, prayer enables us to be aware that we are known by God, and that we assent to be knonw by Him. Lewis needs the assenting because Lewis wants man to be on a personal footing with God with "God revealing Himself as Person." Judaism will reject the latter formulation. There is an infinite barrier between man and God. Prayer overcomes this barrier because God lets it through, but seeing God's face cannot is a logical impossibility.