Two gems from the ever quotable PT Forsyth:
"Prayer is often represented as the great means of the Christian life. But it is no mere means, it is the great end of that life."
"A chief object of all prayer is to bring us to God. But we may attain His presence and come closer to Him by the way we ask Him for other things, concrete things or things of the Kingdom, than by direct prayer for union with Him."
(p. 16, The Soul of Prayer)