What does "if your eye is good" mean in Matthew 6:22?

'If therefore thine eye be single, thy whole body shall be full of light.' The word 'single' must be understood as 'plain, pure'. In the whole New Testament it only appears here and in the parallel-reference in Luke 11:34-36. The corresponding noun 'singleness' (JND: simplicity) appears more often. Ephesians 6:5 and Colossians 3:22 speak of the singleness of the heart and in 2 Corinthians 1:12 and 11:3 of the simplicity before God and the Christ. These references show clearly what the words 'single' and 'simplicity' mean. It is the simplicity and singleness of the heart marked by love and confidence which will not suffer any sin (and be it doubting or wicked ulterior motives) to mar our relation with our Lord and our God and Father. If the look of our eyes is unclouded the whole body will be profiting of it and if the heart is single towards Christ the spiritual life will be full of light. This very light has it's source in God. It helps the youngest believer to understand the Word of God and to put it into practice in his life. It gives clarity and strength to follow a path step by step. It helps us in the difficulties of life (which will not be spared to any disciple of the Lord) to recognise his leading and his hand in them. He will bestow this divine light upon every disciple of his who has the sincere desire to follow him in faithfulness and whose heart is filled with 'the simplicity as to the Christ' (JND).

This gives a single eye, not the duplicity of seeking two contrary things. The eye is the lamp of the body, that is, the receptacle of the light. The light is altogether of God, and to receive that light with singleness of heart, having the one object of rightly sustaining the light, will result in our whole body being full of light, light for our walk, our works, our words, indeed for every department of our existence. This implies simplicity of faith (not duplicity).

But if the eye is evil, perverting what light it receives, there will be no light whatever in the body. In this case the light received is adroitly turned into darkness, a darkness that is "how great!" God's truth must not be trifled with: if perverted, it can plunge one into a state worse than that of ignorance.

This scripture apparently involves a paradox, i.e., an impossible conclusion, because the retina of a man with a single eye receives and transmits the sensation of half the light received by the brain of a person of normal vision. The meaning of a word is, however, best obtained by considering its usage, and Scripture is always its own best commentator. The word translated "single" occurs only in this passage and in the corresponding one in Luke, but the similar noun aplotees occurs eight times and is translated variously as follows:— Thrice as "simplicity." (Rom. 12:8; 2 Cor. 1:12; 2 Cor. 11:3). Twice as "singleness of heart." (Eph. 6:5; Col. 3:22). Twice as "liberality." (2 Cor. 8:2; 2 Cor. 9:13). Once as "bountifulness." (2 Cor. 9:11).

It means literally "one-foldedness" or "simplex structure." We are all familiar with the annoying experience of seeing objects distorted through a common sheet glass window. Light travels slower in glass than in air and in passing through the thicker parts of the glass is retarded so that the wave front of the light becomes bent and clear vision is impossible. The Scriptural meaning of the word is then that there should be no ulterior motive or duplicity in the Christian's action, indeed, he should be what is commonly termed "transparently honest." The perfect example in this as in every other respect was presented in the Lord Jesus Christ and what was true in Him while He was here, should now be true in the Christian.

"The lamp of the body is the eye; if therefore thine eye be single, thy whole body will be light; but if thine eye be wicked, thy whole body will be dark. If therefore the light that is in thee is darkness, how great the darkness!"

It is a question not of the light, which is perfect but of "the eye." Spiritual condition has an immense deal to do with the disciples seeing aright. Our recipiency and discernment, our actual judgment and our practice, depend on the state of our affections. The Lord presents the ready and effectual test. "If therefore thine eye be single, thy whole body will be light; but if thine eye be wicked, thy whole body will be dark."

Christ truly the object before one gives singleness of eye; and where He is simply and exclusively the "one thing" before the soul, the whole body is light. Difficulties vanish. The will of God becomes quite clear. I am surprised and ashamed to have had doubts here and uncertainty there. I recognise to my humiliation that I had been asleep in my ways and had to rise up from among the dead, and then only have Christ shining upon me.

The Light was come and God set it in a due and commanding position that all who saw it might be profited. Never was there one who held forth the light of God as Jesus did. He never wavered, for He was the Holy One, the Undefiled, separate from sinners. There was no fault therefore to be found with the Medium; Jesus not only showed perfect light in what He said, but was the Light Himself. All His perfection on Him; yet how had men treated it? Alas! there are other conditions necessary. "The lamp of the body is thine† eye [therefore] when‡ thine eye is single, thy whole body also is light; but when it is wicked, thy body also is dark." Here we reach so far what man is. It is not here as in John, that Christ is the Light; there we see His personal glory.307 "The body": so most authorities. D, with most Old Lat., has "thy b." †"Thine eye": so ℵpm ABCD, etc., Old Lat. (Edd.). EG, etc., most cursives, Syrrcu sin Arm. have "the eye." ‡AC and later uncials, nearly all cursives, Syrrcu sin, read "therefore" besides "when," which Edd. omit, after ℵBDLΔ, Old Lat. Memph.

But Luke always brings in man's state, or moral condition. "The lamp of the body is thine eye." Light alone outside does not enable a man to see. If the eye, physically, is powerless, the light makes no impression. As in John, the light may be ever so true, but, according to Luke, the eye also enters the account; and by nature it is evil and only so. It is not only Christ as Light that is wanted. Eyes to see must be given; its actual state must be considered. "[Therefore] when thine eye is single, thy whole body also is light." It is a question here of moral purpose. If there be no object to divide the heart's attention, if Christ fills the field of vision, the whole body is light. "But when it is wicked, thy body also is dark." And is there not evil in looking to other objects from Christ, in turning away from the only One Who is worthy? "When it is evil thy body also is dark. See, therefore, that the light which is in thee be not darkness." What darkness is comparable to it? This is moral darkness, and fatal to the soul which can see nothing in Christ, or if it seem to see, is evidently indifferent to Christ, indifferent not to one's own soul alone, but to the eternal truth of God. The eye is evil, the body, therefore, is dark indeed.

'The light of the body is the eye.' In the two previous verses 19 to 21 the Lord Jesus spoke of two kinds of treasures the human heart may hang on to. Now he is talking about two kinds of 'heart-conditions'. He therefore uses the picture of the eye and this again he compares to a lamp.

Lamps are used to give light. Now we cannot say of the eye that it gives light but rather that it takes in the light. The parallel drawn by the Lord Jesus between the lamp and the eye is that the functioning of a shining lamp and that of a good eye lead up to similar results: both of them help men to recognise their surroundings. The better the lamp the brighter the lamp shines and the better the eye the better one can see. Of course the opposite is just a true: as a bad lamp gives poor light so a man with bad eyesight or even blind eyes is not able to see much or even nothing at all. This will be very detrimental to his whole body. Such is the first meaning of the introductory words of the Lord: 'The light of the body is the eye.'

But the Lord Jesus does not teach his disciples about the human eye but rather about the heart which he did already mention in verse 21: 'For where your treasure is, there will your heart be also.' In Scripture the eye is very often used to depict the inner condition of men. The Word of God speaks of 'haughty eyes' (JND) and of 'high looks' (Psalms 18:27; 101:5), of 'blinded eyes' (1 John 2:11), of 'eyes with no fear of God' (Psalm 36:1), of 'evil eyes' (Matt. 20:15; Mark 7:22) and of 'eyes that are not satisfied with riches' (Eccles. 4:8), but also of 'enlightened eyes' (Psalm 19:8) and of a 'bountiful eye' (Pro. 22:9).

The "single eye" does not mean only that we have an eye, but that there is nothing in the eye to prevent our seeing.

And this alone gives a single eye: there is no confusion, no distraction of vision; no unsteadiness therefore, or uncertainty. The eye is the lamp of the body; not the light, but what holds and fixes the light. The light comes from elsewhere: the organ of perception does not create the light, but receives it. The light for us is in the Word alone: it is this that judges and makes plain; but there must be spiritual reception and, for this, capacity of reception, which the Lord indicates here, as it is stated by the apostle (Eph. 1:18, R.V.) to be in the heart and its condition. With the heart set on things above, the eye is single and clear: God is before it, and in His light we see light. Then the whole body becomes full of light: the hands and feet have plenty of it for work and walk. On the contrary, if the eye be evil, the very light may blind one; and when the word of God becomes this, how great may the resulting darkness become.

The great point in ver. 22 is to have the single eye. It is a testing verse. Suppose I am distracted and in uncertainty about anything. Does not this tell me my eye is not single? If I want partly to please myself, and partly to please the Lord, I have not a single eye. But if I have a single eye for a single object, it will make my path easier as I go along.

Very searching words as to earthly possessions are next spoken. No tendency is more deep-seated with all men than that of pursuing, grasping at, and laying up treasures upon earth, though they waste under the action of natural forces as well as the action of violent men. If we really know the Father in heaven, we shall find our treasure in heaven, and there our heart will be; and we have only to have the single eye to see this, and to see all else clearly. Then too our bodies become full of light: that is, we become luminous ourselves. We shall either be dominated by God or by mammon, for we cannot serve two masters. God and mammon are too utterly opposed for that.