VI. The prophet's endeavour to undeceive them. When the prophets they loved and caressed dealt falsely with them, he whom they hated and persecuted dealt faithfully. 1. He shows them their wound. They were loth to see it, very loth to have it searched into; but, if they will allow themselves the liberty of a free thought, they might discover their punishment in their sin (v. 18): "This is thy wickedness because it is bitter. Now thou seest that it is a bitter thing to depart from God, and will certainly be bitterness in the latter end, ch. ii. 19. It produces bitter effects, and grief that reaches unto the heart, touches to the quick, and in the most tender part; the sword reaches to the soul," v. 10. God can make trouble reach the heart even of those that would lay nothing to heart. "And by this thou mayest see what is thy wickedness, that it is a bitter thing, a root of bitterness, that bears gall and wormwood, and that it has reached to the heart; it is the corruption of the soul, of the imagination of the thought of the heart." If the heart were not polluted with sin, it would not be disturbed and disquieted as it is with trouble. 2. He shows them the cure, v. 14. "Since thy wickedness reaches to the heart, there the application must be made. O Jerusalem! wash thy heart from wickedness, that thou mayest be saved." By Jerusalem he means each one of the inhabitants of Jerusalem; for every man has a heart of his own to take care of, and it is personal reformation that must help the public. Every one must return from his own evil way, and, in order to that, cleanse his own evil heart. "And let the heart of the city too be purified, not the suburbs only, the outskirts of it." The vitals of a state must be amended by the reformation of those that have the commanding influence upon it. Note, (1.) Reformation is absolutely necessary to salvation. There is no other way of preventing judgments, or turning them away when we are threatened with them, but taking away the sin by which we have procured them to ourselves. (2.) No reformation is saving but that which reaches the heart. There is heart-wickedness that is defiling to the soul, from which we must wash ourselves. By repentance and faith we must wash our hearts from the guilt we have contracted by spiritual wickedness, by those sins which begin and end in the heart and go no further; and by mortification and watchfulness we must suppress and prevent this heart-wickedness for the future. The tree must be made good, else the fruit will not. Jerusalem was all overspread with the leprosy of sin. Now as the physicians agree with respect to the body when afflicted with leprosy that external applications will do no good, unless physic be taken inwardly to carry off the humours that lurk there and to change the mass of the blood, so it is with the soul, so it is with the state: there will be no effectual reformation of the manners without a reformation of the mind; the mistakes there must be rectified, the corruptions there must be mortified, and the evil dispositions there changed. "Though thou art Jerusalem, called a holy city, that will not save thee, unless thou wash thy heart from wickedness." In the latter part of the verse he reasons with them: How long shall thy vain thoughts lodge within thee? He complains here [1.] Of the delays of their reformation: "How long shall that filthy heart of thine continue unwashed? When shall it once be?" Note, The God of heaven thinks the time long that his room is usurped, and his interest opposed, in our souls, ch. xiii. 27. [2.] Of the root of their corruption, the vain thoughts that lodged within them and defiled their hearts, from which they must wash their hearts. Thoughts of iniquity or mischief, these are the evil thoughts that are the spawn of the evil heart, from which all other wickedness is produced, Matt. xv. 19. These are our own, the conceptions of our own lusts (Jam. i. 15), and they are the most dangerous when they lodge within us, when they are admitted and entertained as guests, and are suffered to continue. Some read it thoughts of affliction, such thoughts as will bring nothing but affliction and misery. Some by the vain thoughts here understand all those frivolous pleas and excuses with which they turned off the reproofs and calls of the word and rendered them ineffectual, and bolstered themselves up in their wickedness. Wash thy heart from wickedness, and think not to say, We are not polluted (ch. ii. 23), or, "We are Jerusalem; we have Abraham to our father," Matt. iii. 8, 9.