Make the heart - The word "heart" here is used in the sense of the "mind" - to denote all their mental powers. It is commonly used in this sense in the Scriptures.

Fat - Gross, heavy, dull, stupid. That is, go and proclaim such "truth" to them as shall have this effect - as shall irritate, provoke, enrage them; truth, whose delivery shall be attended, in their gross and corrupt hearts, with this blinding and infatuating influence the effect would be produced by the corrupt state of their hearts, not by any native tendency of the truth, and still less by any direct divine influence. 'Go, and proclaim truth to a corrupt and sensual people, and the result will be that they will not hear; they are so wicked that they will not attend to it; they will become even more hardened; yet go, and though certain of producing this effect, still proclaim it;' see this passage explained in the notes at John 12:40.

Their ears heavy - Dull, stupid, insensible.

And shut their eyes - The word used here means "to spread over," and then to close. It denotes here the state of mind which is more and more indisposed to attend to the truth.

And be healed - Be restored from the malady of sin; be recovered and pardoned. Sin is often represented as a painful, loathsome malady, and forgiveness as restoration from such a malady; Isaiah 30:26; Psalm 103; Psalm 41:3-4; 2 Chronicles 7:14; Jeremiah 3:22; Jeremiah 17:14. We may learn here,

(1) That the effect of truth is often to irritate people and make them more wicked.

(2) The truth must, nevertheless, be proclaimed.

This effect is not the fault of the truth; and it is often well that the heart should be known, and the true effect should be seen.

Make the heart of this people fat "Gross" - The prophet speaks of the event, the fact as it would actually happen, not of God's purpose and act by his ministry. The prophets are in other places said to perform the thing which they only foretell: -

"Lo! I have given thee a charge this day

Over the nations, and over the kingdoms;

To pluck up, and to pull down;

To destroy, and to demolish;

To build, and to plant."

Make the heart of this people fat,.... Gross and heavy, stupid and unteachable, hard and obdurate; which is sometimes done by the preaching of the Gospel, through the wickedness of man's heart, that being the savour of death unto death to some, just as the sun hardens the clay; or declare that their hearts are thus gross and stupid; or that I will give them up to a judicial hardness of heart:

and make their ears heavy: that they cannot hear the word, so as to understand it; they having stopped the ear, and plucked away the shoulder, it is in righteous judgment that they are given up to such an insensibility as not to be capable of hearing and understanding what is delivered in the ministry of the word:

and shut their eyes; they having wilfully shut their own eyes against all evidence of the Messiah, and the truth of his doctrines, they are given up to a judicial blindness; which still continues upon them, and will until the fulness of the Gentiles is brought in:

lest they see with their eyes, and hear with their ears, and understated with their heart; though only in a notional way, the things relating to the Messiah, the truths of the Gospel, and the ordinances thereof, and what may belong to their outward peace:

and convert; or turn themselves by external repentance and reformation:

and be healed: or forgiven in such sense as to be preserved from national ruin; which God willed not; for seeing they went such great lengths in sin, in rejecting the Messiah, and his Gospel, they were given up to a reprobate mind, to do things that were not convenient, that they might be destroyed; which destruction is after prophesied of.

Make the heart of this people fat, and make their ears heavy, and shut their eyes; lest they see with their eyes, and hear with their ears, and understand with their heart, and convert, and be healed.

6:10 Fat - Stupid and senseless. This making of their hearts fat, is here ascribed to the prophet, as it is ascribed to God in the repetition of this prophecy, John 12:40, because God inflicted this judgment upon them by the ministry of the prophet, partly by way of prediction, foretelling that this would be the effect of his preaching; and partly by withdrawing the light and help of his Spirit. Heavy - Make them dull of hearing. Lest - That they may not be able, as before they were not willing to see. Convert - Turn to God.

10. Make . fat-(Ps 119:17). "Render them the more hardened by thy warnings" [Maurer]. This effect is the fruit, not of the truth in itself, but of the corrupt state of their hearts, to which God here judicially gives them over (Isa 63:17). Gesenius takes the imperatives as futures. "Proclaim truths, the result of which proclamation will be their becoming the more hardened" (Ro 1:28; Eph 4:18); but this does not so well as the former set forth God as designedly giving up sinners to judicial hardening (Ro 11:8; 2Th 2:11). In the first member of the sentence, the order is, the heart, ears, eyes; in the latter, the reverse order, the eyes, ears, heart. It is from the heart that corruption flows into the ears and eyes (Mr 7:21, 22); but through the eyes and ears healing reaches the heart (Ro 10:17), [Bengel]. (Jer 5:21; Eze 12:2; Zec 7:11; Ac 7:57; 2Ti 4:4). In Mt 13:15, the words are quoted in the indicative, "is waxed gross" (so the Septuagint), not the imperative, "make fat"; God's word as to the future is as certain as if it were already fulfilled. To see with one's eyes will not convince a will that is opposed to the truth (compare Joh 11:45, 46; 12:10, 11). "One must love divine things in order to understand them" [Pascal].

be healed-of their spiritual malady, sin (Isa 1:6; Ps 103:3; Jer 17:14).

6:9-13 God sends Isaiah to foretell the ruin of his people. Many hear the sound of God's word, but do not feel the power of it. God sometimes, in righteous judgment, gives men up to blindness of mind, because they will not receive the truth in the love of it. But no humble inquirer after Christ, need to fear this awful doom, which is a spiritual judgment on those who will still hold fast their sins. Let every one pray for the enlightening of the Holy Spirit, that he may perceive how precious are the Divine mercies, by which alone we are secured against this dreadful danger. Yet the Lord would preserve a remnant, like the tenth, holy to him. And blessed be God, he still preserves his church; however professors or visible churches may be lopped off as unfruitful, the holy seed will shoot forth, from whom all the numerous branches of righteousness shall arise.