In these verses the apostle illustrates the difference between believers who rested in Christ only and those judaizers who trusted in the law, by a comparison taken from the story of Isaac and Ishmael. This he introduces in such a manner as was proper to strike and impress their minds, and to convince them of their great weakness in departing from the truth, and suffering themselves to be deprived of the liberty of the gospel: Tell me, says he, you that desire to be under the law, do you not hear the law? He takes it for granted that they did hear the law, for among the Jews it was wont to be read in their public assemblies every sabbath day; and, since they were so very fond of being under it, he would have them duly to consider what is written therein (referring to what is recorded Gen. 16 and 21), for, if they would do this, they might soon see how little reason they had to trust in it. And here, 1. He sets before them the history itself (Gal 4:22, Gal 4:23): For it is written, Abraham had two sons, etc. Here he represents the different state and condition of these two sons of Abraham - that the one, Ishmael, was by a bond-maid, and the other, Isaac, by a free-woman; and that whereas the former was born after the flesh, or by the ordinary course of nature, the other was by promise, when in the course of nature there was no reason to expect that Sarah should have a son. 2. He acquaints them with the meaning and design of this history, or the use which he intended to make of it (Gal 4:24-27): These things, says he, are an allegory, wherein, besides the literal and historical sense of the words, the Spirit of God might design to signify something further to us, and that was, That these two, Agar and Sarah, are the two covenants, or were intended to typify and prefigure the two different dispensations of the covenant. The former, Agar, represented that which was given from mount Sinai, and which gendereth to bondage, which, though it was a dispensation of grace, yet, in comparison of the gospel state, was a dispensation of bondage, and became more so to the Jews, through their mistake of the design of it, and expecting to be justified by the works of it. For this Agar is mount Sinai in Arabia (mount Sinai was then called Agar by the Arabians), and it answereth to Jerusalem which now is, and is in bondage with her children; that is, it justly represents the present state of the Jews, who, continuing in their infidelity and adhering to that covenant, are still in bondage with their children. But the other, Sarah, was intended to prefigure Jerusalem which is above, or the state of Christians under the new and better dispensation of the covenant, which is free both from the curse of the moral and the bondage of the ceremonial law, and is the mother of us all - a state into which all, both Jews and Gentiles, are admitted, upon their believing in Christ. And to this greater freedom and enlargement of the church under the gospel dispensation, which was typified by Sarah the mother of the promised seed, the apostle refers that of the prophet, Isa 54:1, where it is written, Rejoice, thou barren that bearest not; break forth and cry, thou that travailest not; for the desolate hath many more children than she who hath a husband. 3. He applies the history thus explained to the present case (Gal 4:28); Now we, brethren, says he, as Isaac was, are the children of the promise. We Christians, who have accepted Christ, and rely upon him, and look for justification and salvation by him alone, as hereby we become the spiritual, though we are not the natural, seed of Abraham, so we are entitled to the promised inheritance and interested in the blessings of it. But lest these Christians should be stumbled at the opposition they might meet with from the Jews, who were so tenacious of their law as to be ready to persecute those who would not submit to it, he tells them that this was no more than what was pointed to in the type; for as then he that was born after the flesh persecuted him that was born after the Spirit, they must expect it would be so now. But, for their comfort in this case, he desires them to consider what the scripture saith (Gen 21:10), Cast out the bond-woman and her son, for the son of the bond-woman shall not be heir with the son of the free-woman. Though the judaizers should persecute and hate them, yet the issue would be that Judaism would sink, and wither, and perish; but true Christianity should flourish and last for ever. And then, as a general inference from the whole of the sum of what he had said, he concludes (Gal 4:31), So then, brethren, we are not children of the bond-woman, but of the free.

Rejoice, thou barren that bearest not - This quotation is taken from Isa 54:1, and is certainly a promise which relates to the conversion of the Gentiles, as the following clause proves; for the desolate - the Gentile world, hath many more children - is a much larger and more numerous Church, than she - Jerusalem, the Jewish state, which hath a husband - has been so long in covenant with God, living under his continual protection, and in possession of a great variety of spiritual advantages; and especially those offered to her by the Gospel, which she has rejected, and which the Gentiles have accepted.

Now we, brethren, as Isaac was,.... The Ethiopic version reads, "you, brethren"; and so one of Stephens's copies. As the two women, Hagar and Sarah, might be, and are allegorized; so likewise their respective offspring. Isaac signified, and was a type and figure of Abraham's spiritual seed, whether Jews or Gentiles, under the Gospel dispensation: and as he was, so they are,

the children of promise; as Isaac was promised unto Abraham, so were this spiritual seed, when it was said unto him, that he should be the father of many nations, as he is the father of us all, even of all them that believe, be they of what nation soever; and as Isaac was born by virtue, and in consequence of a promise made to Abraham of God's free good will and pleasure, and his generation and conception were beyond the strength and course of nature, were the effects of a divine power, and were something supernatural; so this spiritual seed are born again, by virtue, and in consequence of a promise, not only made to Abraham, but to the Lord Jesus Christ, the head of the covenant, that he should see his seed, enjoy a numerous offspring, and which should endure for ever; and also to the church, of whom it is said, that this and that man should be born in her; and particularly in consequence of the promise cited in the foregoing verse, from whence these words are an inference, deduction, or illustration: and these children of the promise, so called from hence, are born again, above and beyond the strength of nature; not through the power and free will of man, but through the abundant mercy and sovereign will of God, by his powerful and efficacious grace, and by the word of promise, the Gospel, as a means. Moreover, to these children, or spiritual seed of Abraham, signified by Isaac, do all the promises belong, as that of God, as a covenant God gave unto them; of Christ, as a Saviour and Redeemer; of the Holy Spirit, as a sanctifier and comforter; and of all good things, of temporal mercies, so far as are for their real good; and of all spiritual blessings, as righteousness, peace, pardon, comfort, all supplies of grace, and eternal life: and these likewise receive these promises; the Holy Spirit, as a spirit of promise, opens and applies them to them, puts them into the hand of faith, and enables them to plead them with God, and to believe the performance of them; so that this character in all respects agrees with them.

(Isa 54:1).

thou barren--Jerusalem above: the spiritual Church of the Gospel, the fruit of "the promise," answering to Sarah, who bore not "after the flesh": as contrasted with the law, answering to Hagar, who was fruitful in the ordinary course of nature. Isaiah speaks primarily of Israel's restoration after her long-continued calamities; but his language is framed by the Holy Spirit so as to reach beyond this to the spiritual Zion: including not only the Jews, the natural descendants of Abraham and children of the law, but also the Gentiles. The spiritual Jerusalem is regarded as "barren" while the law trammeled Israel, for she then had no spiritual children of the Gentiles.

break forth--into crying.

cry--shout for joy.

many more--Translate as Greek, "Many are the children of the desolate (the New Testament Church made up in the greater part from the Gentiles, who once had not the promise, and so was destitute of God as her husband), more than of her which hath an (Greek, 'THE') husband (the Jewish Church having GOD for her husband, Isa 54:5; Jer 2:2)." Numerous as were the children of the legal covenant, those of the Gospel covenant are more so. The force of the Greek article is, "Her who has THE husband of which the other is destitute."