Still it may be asked, what is the use of prayer at all, whether made in words or in meditation of things, if God knows already what is necessary for us. The mental posture of prayer calms and purifies the soul, and makes it of more capacity to receive the divine gifts which are poured into it. For God does not hear us for the prevailing force of our pleadings; He is at all times ready to give us His light, but we are not ready to receive it, but prone to other things.
There is then in prayer a turning of the body to God, and a purging of the inward eye, whilst those worldly things which we desired are shut out, that the eye of the mind made single might be able to bear the single light, and in it abide with that joy with which a happy life is perfected.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Serm. in Mont., ii, 3