'Of course it is very difficult to keep God only before one for more than a few seconds. Our minds are in ruins before we bring them to Him & the rebuilding is gradual. It may help to practice concentration on other objects twice a week quite apart from one's prayer: i.e. sit down looking at some physical object (say, a flower) and try for a few seconds to attend exclusively to it, quietly (never impatiently) rejecting the train of thought & imagination wh. keep starting up.'
CS Lewis in Walter Hooper (Ed.), The Collected Letters of CS Lewis Vol. II, p.826.
