Matthew 6:22 - Joseph Benson’s Commentary on the Old and New Testaments

The light Or lamp rather, as ο λυχνος should be translated, of the body, is the eye That is, it is by the eye that a person has light to direct him in his bodily motions, and in the use of his bodily members. If therefore thine eye be single Απλους, simple, not mixed with noxious humours, but clear and sound; so both Chrysostom and Theophylact understand the expression, considering it as synonymous with υγιης, whole; thy whole body shall be full of light Every member of thy body shall be enlightened by the light of thine eye, and directed to perform its proper office. But if thine eye be evil Gr. πονηρος, rendered νοσωδης, morbid, by Theophylact, and distempered, by Dr. Campbell, who observes, “that there is no reference to the primitive meaning of απλους, single, is evident from its being contrasted to πονηρος, evil, bad, or disordered, and not to διπλους, double. Our Lord's argument,” adds he, “stands thus: The eye is the lamp of the body: from it all the other members derive their light. Now if that which is the light of the body be darkened, how miserable will be the state of the body! how great will be the darkness of those members which have no light of their own, but depend entirely on the eye!” Thus “if the conscience, that mental light which God has given to man for regulating his moral conduct, be itself vitiated, what will be the state of his appetites and passions, which are naturally blind and precipitate?” To the same purpose speaks Macknight, only using the term reason, instead of conscience. “As the body must be well enlightened if its eye is sound and good, or greatly darkened if it is spoiled with noxious humours; so the mind must be full of life, if reason, its eye, is in a proper state; or full of darkness, if it is perverted by covetousness, and other worldly passions; but with this difference, that the darkness of the mind is infinitely worse than the darkness of the body, and attended with worse consequences, inasmuch as the actions of the mind are of far greater importance to happiness than those of the body.” Baxter and Dr. Doddridge understand the words in nearly the same sense, interpreting the word eye of the practical judgment. “If thy judgment be sound,” says the former, “and thou knowest the difference between laying up treasure in heaven and on earth, it will rightly guide all the actions of thy heart and life: but if thy judgment be blinded in this great affair, it will misguide thy love, thy choice, and all the tenor of thy life: if thy judgment then be blind, which must guide thee, what a miserable erroneous wretch wilt thou be! and how dismal will that error prove!” Or, as the doctor expresses it, “If the maxims you lay down to yourselves are wrong, how very erroneous must your conduct be!”