{7} The light of the body is the eye: if therefore thine {g} eye be single, thy whole body shall be full of light.

(7) Men maliciously and wickedly put out even the little light of nature that is in them.

(g) The judgment of the mind: that as the body is with the eyes, so our whole life may be ruled with right reason, that is to say, with the Spirit of God who gives light to us.

People's New Testament

6:22,23 The light of the body is the eye. This is not an abrupt transition, but bears on the same subject. If one's eye is diseased, all he sees is wrong. So the mind, or conscience, is the light of the soul. If these be darkened, all is darkness; if these see aright, all is light.

Wesley's Notes

6:22 The eye is the lamp of the body - And what the eye is to the body, the intention is to the soul. We may observe with what exact propriety our Lord places purity of intention between worldly desires and worldly cares, either of which directly tend to destroy. If thine eye be single - Singly fixed on God and heaven, thy whole soul will be full of holiness and happiness. If thine eye be evil - Not single, aiming at any thing else.

Jamieson-Fausset-Brown Bible Commentary

22. The light-rather, "the lamp."

of the body is the eye: if therefore thine eye be single-simple, clear. As applied to the outward eye, this means general soundness; particularly, not looking two ways. Here, as also in classical Greek, it is used figuratively to denote the simplicity of the mind's eye, singleness of purpose, looking right at its object, as opposed to having two ends in view. (See Pr 4:25-27).

thy whole body shall be full of light-illuminated. As with the bodily vision, the man who looks with a good, sound eye, walks in light, seeing every object clear; so a simple and persistent purpose to serve and please God in everything will make the whole character consistent and bright.

Matthew Henry's Concise Commentary

6:19-24 Worldly-mindedness is a common and fatal symptom of hypocrisy, for by no sin can Satan have a surer and faster hold of the soul, under the cloak of a profession of religion. Something the soul will have, which it looks upon as the best thing; in which it has pleasure and confidence above other things. Christ counsels to make our best things the joys and glories of the other world, those things not seen which are eternal, and to place our happiness in them. There are treasures in heaven. It is our wisdom to give all diligence to make our title to eternal life sure through Jesus Christ, and to look on all things here below, as not worthy to be compared with it, and to be content with nothing short of it. It is happiness above and beyond the changes and chances of time, an inheritance incorruptible. The worldly man is wrong in his first principle; therefore all his reasonings and actions therefrom must be wrong. It is equally to be applied to false religion; that which is deemed light is thick darkness. This is an awful, but a common case; we should therefore carefully examine our leading principles by the word of God, with earnest prayer for the teaching of his Spirit. A man may do some service to two masters, but he can devote himself to the service of no more than one. God requires the whole heart, and will not share it with the world. When two masters oppose each other, no man can serve both. He who holds to the world and loves it, must despise God; he who loves God, must give up the friendship of the world.