"Why did God command prayer?
Whatever God does, he does for good reasons
Three reasons God commands us to pray corresponds to our three deepest needs, the fundamental needs of the three powers of our soul:prayer gives truth to our mind, goodness to our will, and beauty to our heart. "The true, the good, and the beautiful" are the three things we need and love the most, because they are three attributes of God.
Prayer gives truth to our mind because it puts us in the presence of Truth itself, the divine Mind who designed our minds and our lives and our whole universe.
It gives goodness to our will because it puts us "on line" with God, in love with the God who is love and goodness. That is his essence. In prayer we become like the God we pray to and conform to; we catch the good infection of Godliness by contact.
It gives beauty to our heart because it plunges us into the heart of God, which is the eternal energy of infinite joy. That is why it gives us joy and peace and delight and happiness."
-Prayer for Beginners by Peter Kreeft
I just love that.