Prayer is a most profitable and expedient means of obtaining purity of heart, the eradication of sin, and a receptiveness to virtue. Not that you should imagine that the purpose of your prayer is to tell the Lord what you want; for he knows well enough what you need. Rather, the purpose of prayer is to make your ready and able to receive as a clean vessel the grace that our Lord would freely give to you.
Now, this grace may not be experienced until you are tried and purified by the fire of desire in fervent prayer. For though it is true that prayer is not the cause of our Lord’s grace being given, it is nevertheless a channel by which that grace freely flows into a soul.
Walter Hilton, Toward a Perfect Love: The Spiritual Counsel of Walter Hilton (Vancouver: Regent College Publishing, 2001), 47.