Ephesians 4:18

2. Having the understanding darkened - This is the second instance alleged by the apostle of the degradation of the Gentiles. Having no means of knowledge, the heart, naturally dark, became more and more so by means of habitual transgression; every thing in the Gentile system having an immediate tendency to blind the eyes and darken the whole soul.

3. Being alienated from the life of God - The original design of God was to live in man; and the life of God in the soul of man was that by which God intended to make man happy, and without which true happiness was never found by any human spirit: from this through the ignorance that was in them, δια την αγνοιαν την ουσαν, through the substantial or continually existing ignorance, which there was nothing to instruct, nothing to enlighten; for the most accurate writings of their best philosophers left them entirely ignorant of the real nature of God. And if they had no correct knowledge of the true God they could have no religion; and if no religion, no morality. Their moral state became so wretched that they are represented as abhorring every thing spiritual and pure, for this is the import of the word απηλλοτριωμενοι (which we translate alienated) in some of the best Greek writers. They abhorred every thing that had a tendency to lay any restraint on their vicious passions and inclinations.

4. Blindness of their heart - Δια την πωρωσιν· Because of the callousness of their hearts. Callous signifies a thickening of the outward skin of any particular part, especially on the hands and feet, by repeated exercise or use, through which such parts are rendered insensible. This may be metaphorically applied to the conscience of a sinner, which is rendered stupid and insensible by repeated acts of iniquity.

Having the understanding darkened - That is, because they were alienated from the true God, and particularly because of "the blindness of their hearts." The apostle does not say that this was a "judicial" darkening of the understanding; or that they might not have perceived the truth; or that they had no ability to understand it. He speaks of a simple and well-known fact - a fact that is seen now as well as then that the understanding becomes darkened by indulgence in sin. A man who is intemperate, has no just views of the government of the appetites. A man who is unchaste, has no perception of the loveliness of purity. A man who is avaricious or covetous, has no just views of the beauty of benevolence. A man who indulges in low vices, will weaken his mental powers, and render himself incapable of intellectual effort. Indulgence in vice destroys the intellect as well as the body, and unfits a man to appreciate the truth of a proposition in morals, or in mathematics, or the beauty of a poem, as well as the truth and beauty of religion.

Nothing is more obvious than that indulgence in sin weakens the mental powers, and renders them unfit for high intellectual effort. This is seen all over the pagan world now - in the stolid, stupid mind; the perverted moral sense; the incapacity for profound or protracted mental effort, as really as it was among the pagans to whom Paul preached. The missionary who goes among the pagan has almost to create an "intellect" as well as a "conscience," before the gospel will make an impression. It is seen, too, in all the intellect of the bar, the senate, the pulpit, and the medical profession, that is ruined by intemperance, and in the intellect of multitudes of young men wasted by licentiousness and drunkenness. I know that under the influence of ambition and stimulating drinks, the intellect may seem to put forth unnatural efforts, and to glow with an intensity nowhere else seen. But it "soon burns out" - and the wastes of such an intellect become soon like the hardened scoriae of the volcano, or the cinders of the over-heated furnace. Learn hence, that if a man wishes to be blessed with a clear understanding, he should he a "good man." He who wishes a mind well balanced and clear, should fear and love God; and had Christianity done no other good on earth than to elevate the "intellect" of mankind, it would have been the richest blessing which has ever been vouchsafed to the race. It follows, too, that as man has debased his "understanding" by sin, it is needful to make an exertion to elevate it again: and hence a large part of the efforts to save people must consist in patient "instruction." Hence, the necessity of schools at missionary stations.

Being alienated - see the notes on Ephesians 2:12.

From the life of God - From a life "like" that of God, or a life of which he is the source and author. The meaning is, that they lived a life which was "unlike" God, or which he could not approve. Of the truth of this in regard to the pagan everywhere, there can be no doubt; see the notes on Romans 1.

Through the ignorance that is in them - The ignorance of the true God, and of what constituted virtue; compare notes on Romans 1:20-23.

Because of the blindness of their heart - Margin, "hardness." Hardness is a better word. It is a better translation of the Greek; and it better accords with the design of the apostle. Here the reason is stated why they lived and acted as they did, and why the "understanding" was blinded. It is not that God has enfeebled the human intellect by a judicial sentence on account of the sin of Adam, and made it incapable of perceiving I the truth. It is not that there is any I deficiency or incapacity of natural powers. It is not that the truths of religion are so exalted that man has no natural ability to understand them, for they may be as well understood as any other truth; see the notes on 1 Corinthians 1:14. The simple reason is, "the hardness or the heart." That is the solution given by an inspired apostle, and that is enough. A man who has a blind and hard heart sees no beauty in truth, and feels not its force, and is insensible to all its appeals. Learn, then:

(1) That people are to blame for the blindness of their understanding. Whatever proceeds from a "wicked heart" they are responsible for. But for mere "inferiority of intellect" they would not be to blame.

(2) they are under obligation to repent and love God. If it was required of them to enlarge their intellects, or create additional faculties of mind, they could not be bound to do it. But where the whole thing required is to have a "better heart," they may be held responsible.

(3) the way to elevate the understandings of mankind is to purify the heart. The approach must be made through the affections. Let people "feel" right toward God, and they will soon "think" right; let the heart be pure, and the understanding will be clear.

(Doubtless there is a reciprocal influence between the dark mind and depraved heart. The one acts on the other. Admitting that the understanding is affected "first," through the will or heart, and that it is a bad heart which makes a spiritually dark mind, still the fact remains the same, that "in consequence of our union with Adam, in consequence of the fall," all our faculties, understanding, will, affections, have been corrupted. See the supplementary notes, Romans 5)

4:18 Having their understanding darkened, through the ignorance that is in them - So that they are totally void of the light of God, neither have they any knowledge of his will.Being alienated from the life of God - Utter strangers to the divine, the spiritual life. Through the hardness of their hearts - Callous and senseless. And where there is no sense, there can be no life.