Verse 6. - The Lord will circumcise thine heart; "when thou wilt become better, God will help thereto (cf. Deuteronomy 10:16)" (Herxheimer). When Israel should return to the Lord, he would take away from them the evil heart of unbelief, and give them the new heart and the right spirit. "Qui pravis affectibus renunciat is circumcisus corde dicitur" (Rosenmüller. Cf. Jeremiah 31:33; Jeremiah 32:39; Ezekiel 11:19, etc.; Ezekiel 36:26; Romans 2:29; Colossians 2:11).

30:1-10 In this chapter is a plain intimation of the mercy God has in store for Israel in the latter days. This passage refers to the prophetic warnings of the last two chapters, which have been mainly fulfilled in the destruction of Jerusalem by the Romans, and in their dispersion to the present day; and there can be no doubt that the prophetic promise contained in these verses yet remain to come to pass. The Jewish nation shall in some future period, perhaps not very distant, be converted to the faith of Christ; and, many think, again settled in the land of Canaan. The language here used is in a great measure absolute promises; not merely a conditional engagement, but declaring an event assuredly to take place. For the Lord himself here engages to circumcise their hearts; and when regenerating grace has removed corrupt nature, and Divine love has supplanted the love of sin, they certainly will reflect, repent, return to God, and obey him; and he will rejoice in doing them good. The change that will be wrought upon them will not be only outward, or consisting in mere opinions; it will reach to their souls. It will produce in them an utter hatred of all sin, and a fervent love to God, as their reconciled God in Christ Jesus; they will love him with all their hearts, and with all their soul. They are very far from this state of mind at present, but so were the murderers of the Lord Jesus, on the day of Pentecost; who yet in one hour were converted unto God. So shall it be in the day of God's power; a nation shall be born in a day; the Lord will hasten it in his time. As a conditional promise this passage belongs to all persons and all people, not to Israel only; it assures us that the greatest sinners, if they repent and are converted, shall have their sins pardoned, and be restored to God's favour.And the Lord thy God will circumcise thine heart, and the heart of thy seed,.... No mention is made of circumcision of the flesh, which will now be out of use with the Jews; they being fully convinced of the abrogation of the ceremonial law by the Messiah, whom they will now receive. It is spiritual circumcision only that is here spoken of, with which the Jews will be circumcised, when they shall be pricked and cut to the heart, and be thoroughly convinced of sin; when the iniquity of their hearts will be laid open to them, and they put to pain, and filled with shame and loathing for it; when the hardness of their hearts will be removed, and the foolishness of them will be exposed and taken away, and they will be made willing to part with their sins, and with their own righteousness; when the graces of the Spirit will be implanted in them, and the blood of Christ applied to them for pardon and cleansing. This is the circumcision made without hands, which is not of men, but of God; what he calls for, and exhorts unto, as being necessary, Deuteronomy 10:16; he here promises to do; and deed none but himself can do it; for he only can come at the hearts of men, to take anything out of them, or put anything into them; it is he that opens the heart, softens, quickens, enlightens, and purifies it: Baal Hatturim says this respects the times of the Messiah:

to love the Lord thy God with all thine heart, and with all thy soul; which, though the duty of every man, is performed by none but those that have the grace of God; there is no love to God in the heart before this inward and spiritual circumcision of it: it is a fruit of the Spirit in conversion when the affections are taken off of other things, and set on Christ; when a man sees his sin and his Saviour, and the one is odious, and the other precious; when the blessings of grace are applied, and the love of God is shed abroad in the heart, which cause love to God and Christ again:

that thou mayest live; spiritually and eternally; for there is no spiritual life in the soul till the heart is circumcised, or, in other words, regenerated and renewed; then it is quickened; then a man lives a life of faith on Christ, of holiness from him, communion with him, and has both an open right unto, and meetness for, eternal life.