4:30 What saith the scripture? See Ge 21:10.
Cast out the bondwoman and her son. The allegory will hold good still further. Abraham, when it was impossible that the two families should get along in peace, cast out the bondwoman and her son.
For the son of the bondwoman shall not be heir with the son of the freewoman. So, too, the Jews, the children of the old covenant, had lost the divine favor, and the children of the promise, whether Jews or Gentiles, made heirs.
4:30 But what saith the scripture - Showing the consequence of this. Cast out the bondwoman and her son - Who mocked Isaac. In like manner will God cast out all who seek to be justified by the law; especially if they persecute them who are his children by faith. Gen 21:10.
4:28-31 The history thus explained is applied. So then, brethren, we are not children of the bond-woman, but of the free. If the privileges of all believers were so great, according to the new covenant, how absurd for the Gentile converts to be under that law, which could not deliver the unbelieving Jews from bondage or condemnation! We should not have found out this allegory in the history of Sarah and Hagar, if it had not been shown to us, yet we cannot doubt it was intended by the Holy Spirit. It is an explanation of the subject, not an argument in proof of it. The two covenants of works and grace, and legal and evangelical professors, are shadowed forth. Works and fruits brought forth in a man's own strength, are legal. But if arising from faith in Christ, they are evangelical. The first covenant spirit is of bondage unto sin and death. The second covenant spirit is of liberty and freedom; not liberty to sin, but in and unto duty. The first is a spirit of persecution; the second is a spirit of love. Let those professors look to it, who have a violent, harsh, imposing spirit, towards the people of God. Yet as Abraham turned aside to Hagar, so it is possible a believer may turn aside in some things to the covenant of works, when through unbelief and neglect of the promise he acts according to the law, in his own strength; or in a way of violence, not of love, towards the brethren. Yet it is not his way, not his spirit to do so; hence he is never at rest, till he returns to his dependence on Christ again. Let us rest our souls on the Scriptures, and by a gospel hope and cheerful obedience, show that our conversation and treasure are indeed in heaven.
