I. God here promises that he will work a good work in them, to qualify them for the good work he intended to bring about for them, v. 25-27. We had promises to the same purport, ch. xi. 18-20. 1. That God would cleanse them from the pollutions of sin (v. 25): I will sprinkle clean water upon you, which signifies both the book of Christ sprinkled upon the conscience to purify that and to take away the sense of guilt (as those that were sprinkled with the water of purification were thereby discharged from their ceremonial uncleanness) and the grace of the Spirit sprinkled on the whole soul to purify it from all corrupt inclinations and dispositions, as Naaman was cleansed from his leprosy by dipping in Jordan. Christ was himself clean, else his blood could not have been cleansing to us; and it is a Holy Spirit that makes us holy: From all your filthiness and from all your idols will I cleanse you. And (v. 29) I will save you from all your uncleannesses. Sin is defiling, idolatry particularly is so; it renders sinners odious to God and burdensome to themselves. When guilt is pardoned, and the corrupt nature sanctified, then we are cleansed from our filthiness, and there is no other way of being saved from it. This God promises his people here, in order to his being sanctified in them, v. 23. We cannot sanctify God's name unless he sanctify our hearts, nor live to his glory, but by his grace. 2. That God would give them a new heart, a disposition of mind excellent in itself and vastly different from what it was before. God will work an inward change in order to a universal change. Note, All that have an interest in the new covenant, and a title to the new Jerusalem, have a new heart and a new spirit, and these are necessary in order to their walking in newness of life. This is that divine nature which believers are by the promises made partakers of. 3. That, instead of a heart of stone, insensible and inflexible, unapt to receive any divine impressions and to return any devout affections, God would give a heart of flesh, a soft and tender heart, that has spiritual senses exercised, conscious to itself of spiritual pains and pleasures, and complying in every thing with the will of God. Note, Renewing grace works as great a change in the soul as the turning of a dead stone into living flesh. 4. That since, besides our inclination to sin, we complain of an inability to do our duty, God will cause them to walk in his statutes, will not only show them the way of his statutes before them, but incline them to walk in it, and thoroughly furnish them with wisdom and will, and active powers, for every good work. In order to this he will put his Spirit within them, as a teacher, guide, and sanctifier. Note, God does not force men to walk in his statutes by external violence, but causes them to walk in his statutes by an internal principle. And observe what use we ought to make of this gracious power and principle promised us, and put within us: You shall keep my judgments. If God will do his part according to the promise, we must do ours according to the precept. Note, The promise of God's grace to enable us for our duty should engage and quicken our constant care and endeavour to do our duty. God's promises must drive us to his precepts as our rule, and then his precepts must send us back to his promises for strength, for without his grace we can do nothing.