The light of the body is the eye: if therefore your eye be sound, your whole body shall be full of light.
All Commentaries on Matthew 6:22 Go To Matthew 6
Augustine of Hippo
AD 430
And here He makes it manifest that He gives all these precepts with a view to the cleansing of the heart.
And this passage we are to understand in such a way as to learn from it that all our works are pure and well-pleasing in the sight of God, when they are done with a single heart, i.e. with a heavenly intent, having that end of love in view; for love is also the fulfilling of the law. Hence we ought to take the eye here in the sense of the intent itself, wherewith we do whatever we are doing; and if this be pure and right, and looking at that which ought to be looked at, all our works which we perform in accordance therewith are necessarily good. And all those works He has called the whole body; for the apostle also speaks of certain works of which he disapproves as our members, and teaches that they are to be mortified, saying, Mortify therefore your members which are upon the earth; fornication, uncleanness, covetousness, and all other such things.