Isaac: 4. Isaac Abiding, Hagar and Ishmael Dismissed

Genesis 21:8-21
GOD knows how to rectify the false position that springs from unbelief. We may therefore look to Him and His word, and have only to obey. But if this ever costs the flesh not a little, blessing surely follows self-denying submission to His will.
“And the child grew and was weaned; and Abraham made a great feast on the day that Isaac was weaned. And Sarah saw Hagar the Egyptian s son, whom she had borne to Abraham, mocking. And she said to Abraham, Cast out this maidservant and her son; for this maid-servant's son shall not be heir with my son, with Isaac. And the thing was very grievous in Abraham's sight because of his son. And God said to Abraham, Let it not be grievous in thy sight because of the lad, and because of thy maid-servant: [in] all that Sarah saith to thee, hearken to her voice; for in Isaac shall a seed be called to thee. But also the maid-servant's son will I make a nation, because he is thy seed. And Abraham rose up early in the morning, and took bread and a leathern bottle of water and gave [it] to Hagar, putting [it] on her shoulder, and the child, and sent her away; and she departed and wandered in the wilderness of Beer-sheba. And the water from the bottle was exhausted; and she cast the child under one of the shrubs. And she went and sat down over against [him] about a bowshot; for she said, I will not look on the death of the child. And she sat over against [him], and lifted up her voice and wept. And God heard the lad's voice; and God's angel called to Hagar out of the heavens, and said to her, What aileth thee, Hagar? Fear not; for God hath heard the lad's voice there where he is. Arise, take the lad, and hold him in thy hand, for a great nation will I make him. And God opened her eyes, and she saw a well of water, and she went and filled the bottle with water, and gave the lad drink. And God was with the lad; and he grew and dwelt in the wilderness, and became as he grew up an archer. And he dwelt in the wilderness of Paran; and his mother took him a wife out of the land of Egypt” (vers. 8-21).
As the child born and the son given typified the Son of the Highest, it was meet that the occasion should be marked by consequences of the gravest. What can distinguish inspiration more than the lesson the apostle in Gal. 4:22-2622For it is written, that Abraham had two sons, the one by a bondmaid, the other by a freewoman. 23But he who was of the bondwoman was born after the flesh; but he of the freewoman was by promise. 24Which things are an allegory: for these are the two covenants; the one from the mount Sinai, which gendereth to bondage, which is Agar. 25For this Agar is mount Sinai in Arabia, and answereth to Jerusalem which now is, and is in bondage with her children. 26But Jerusalem which is above is free, which is the mother of us all. (Galatians 4:22‑26) draws from that which seems on the surface a mere domestic occurrence? “For it is written that Abraham had two sons; one of the maid-servant, and one of the free-woman. But he that was of the maid-servant was born according to flesh, and he that was of the free-woman through the promise. Which things have an allegorical sense; for these [women] are two covenants: one from Mount Sinai, gendering unto bondage, which is Hagar. For Hagar is Mount Sinai in Arabia, and answers to the present Jerusalem; for she is in bondage with her children; but the Jerusalem above is free, which is our mother.”
This was God's purpose, though none apprehend it save those who have Christ's mind. Hence the unbelieving Jews fill the place, not of Isaac, but of Ishmael. They are as far as possible from suspecting that they are only born according to flesh, and persecute him that is born according to Spirit. Yet they cannot deny that their mother is the Sinai covenant, and that they are cast out by God. They have the law's curse as transgressors; they have not a shred of the promise to cover their nakedness. Their own prophets declare that they are not God's people, and if without a false god without the True, as they have plainly neither land nor prince; and this because they rejected, first Jehovah, next His Christ.
But the apostle goes a great deal farther; and though he does not confound the believing Gentiles with Israel, like the theologians of Christendom, he shows that all who take their stand on law come under the curse (Gal. 3:1010For as many as are of the works of the law are under the curse: for it is written, Cursed is every one that continueth not in all things which are written in the book of the law to do them. (Galatians 3:10)). Thus the principle applies in all its force, indeed emphatically, to Gentiles, who have not the excuse of inveterate Jewish prejudice. It is to fall from grace, through which alone can souls be saved. Law cannot save but condemn sinners; and if grace be mixed with law, the mixture is unavailing: grace only can save the guilty and lost. The Galatians who were bewitched to tack law on to grace, he solemnly warns of utter ruin, so sure that as many as are of works of law (i.e., on this principle) are under curse. After having begun in Spirit, how senseless for them to seek perfection in flesh! The law itself, in the tale of Abraham's two sons, convicts of folly those who thus abuse the law. Its lawful application (1 Tim. 1:99Knowing this, that the law is not made for a righteous man, but for the lawless and disobedient, for the ungodly and for sinners, for unholy and profane, for murderers of fathers and murderers of mothers, for manslayers, (1 Timothy 1:9)) is not to a righteous person, but to lawless and insubordinate, to impious and sinful, to unholy and profane, to whatever in short is opposed to the healthful doctrine Paul taught.
Hence the peremptory tone of the apostle to the endangered Galatians. He will have this “leaven” extirpated, whatever it cost. It was a deeper peril than the “leaven” which he enjoins the Corinthians to purge out. Not even a moral man could defend the gross inconsistency with Christ and His sacrifice of having the wicked man in their midst. But the fair show in flesh set up in the Galatian churches was subtler, and a denial of the grace which the gospel proclaims, when law had been proved to be simply a ministry of death and condemnation. What then “saith the scripture? Cast out the maid-servant and her son; for the son of the maid-servant shall in no wise be heir with the son of the free-woman.” The Judaizing Gentile is even more blamable than the Jew. Alas! the ritualism of the day is incomparably worse still and growingly apostate; for not content with the legal forms of Israel, it incorporates the idolatries of the heathen also, as in the adoration of the sacramental elements, &c.
Yet is it affecting to know God's goodness to Abraham's seed according to flesh. When the mother yielded to despair, and laid her son down to die at a distance from her, “God heard the lad's voice;” and His angel bids Hagar hold him in her hand. Had not Jehovah called his name Ishmael, because He had heard her affliction? And as she was then by a fountain called Beer-la-hai-roi Well of the living who was seen (or, seeth me) from the name of Him that spoke to her (ch. 16), so now God opened her eyes to see a well of water whence she gave the lad drink. If she forgot the divine assurance of a numberless multitude in general to spring from her, and that Ishmael should dwell in the presence of all his brethren, God remembered him and declares that He will make him a great nation. So it has been. There they are with the same characteristics to this day.