Abraham: Chapter 21

Genesis 21
The power of God was now accomplishing what His mouth had promised, The child is born of Sarah, the son given to Abraham, type of Him, the Son, whom God sent forth, when the fullness of the time was come, to effect redemption, and be the center of all His purposes for heaven on earth, and the judge of all He will cast into hell.
“And Jehovah visited Sarah as he had said, and Jehovah did unto Sarah as he had spoken. For Sarah conceived, and bare Abraham a son in his old age, at the set time of which God had spoken to him. And Abraham called the name of his son that was born unto him, whom Sarah bare to him, Isaac. And Abraham circumcised his son Isaac, being eight days old, as God had commanded him. And Abraham was an hundred years old when his son Isaac was born unto him. And Sarah said, God hath made me to laugh, so that all that hear will laugh with me. And she” said, Who would have said unto Abraham, that Sarah should have given children suck? for I have born him a son in his old age.” (Vers. 1-7.)
Thus was Isaac's birth the occasion of joy in measure, as his very name imports, when Sarah laughed no more in unbelief, as once (Gen. 18:12-1512Therefore Sarah laughed within herself, saying, After I am waxed old shall I have pleasure, my lord being old also? 13And the Lord said unto Abraham, Wherefore did Sarah laugh, saying, Shall I of a surety bear a child, which am old? 14Is any thing too hard for the Lord? At the time appointed I will return unto thee, according to the time of life, and Sarah shall have a son. 15Then Sarah denied, saying, I laughed not; for she was afraid. And he said, Nay; but thou didst laugh. (Genesis 18:12‑15)), but in gladness of heart, as in the fellowship of all that hear of the goodness of the Lord. It is a lovely witness to the power of grace when faith thus gives the victory in what had been one's weakness, and sin, and shame. And so, if Abraham gives the name to his son, Sarah needs, no prophet, but explains the mind of God in it for herself, and forever.
But another sight of the family of faith is next vouchsafed to us. “And the child grew, and was weaned: and Abraham made a great feast the same day that Isaac was weaned. And Sarah saw the son of Hagar the Egyptian, which she had born unto Abraham, mocking. Wherefore she said unto Abraham, Cast out this bondwoman and her son: for the son of this bondwoman shall not be heir with my son, even with Isaac. And the thing was very grievous in Abraham's sight because of his son. And God said unto Abraham, Let it not be grievous in thy sight because of the lad, and because of thy bondwoman; in all that Sarah hath said unto thee, hearken unto her voice; for in Isaac shall thy seed be called. And also of the son of the bondwoman will I make a nation, because he is thy seed.” (Vers. 8-13.) Of this incident, which our light hearts might quickly pass over, the Holy Ghost makes a great deal in the two Epistles of the New Testament, which either assert or vindicate the fundamental truth of justification by faith.
The first occurs in Gal. 4, where the apostle is convicting the bewitched Galatians of their folly in departing from grace to law. If they desired to be under the law, why not hear the law? The two sons of Abraham should have had a voice to every believer. One was by a slave, the other by a free woman; one born after the flesh, the other by promise, as the mothers answered to the two covenants, Jerusalem that was in bondage with her children, and Jerusalem which is above, the free mother of the free. But this, though much, is not all; for after citing from Isaiah a marvelous testimony to the reckoning of grace during the desolation of Jerusalem, the tale of the child of promise is again used to show (1) that as he that was born after the flesh then persecuted him that was after the Spirit, so it is now; (2) that the sentence of scripture is, Cast out the bondmaid and her son; for the eon of the bondwoman shall not be heir with the son of the free-woman. Grace refuses partnership with law or flesh. The child of promise alone inherits.
It is the more instructive and important to note that in this transaction Abraham was weak, and Sarah strong. He did not give glory to God as she did; hence God called on Abraham to hearken to Sarah's voice, whatever might be the natural subjection of wife to husband—a subjection in which the Apostle Peter expressly cites this very Sarah as an admirable pattern to Christian women generally. But here the weaker vessel was by grace the stronger of the two, and Abraham must not regard Sarah's feeling as the mere affronted pride of the mistress who could not brook the airs of aspiring and mocking Ishmael. She was in the secret of Jehovah more deeply than her husband; while he was allowing unduly the claims of flesh, and was grieved at the proposal of expelling the bondmaid's son from the house...But so it must be according to God. Sarah was right. Her child was of promise, as the word was which declared Jehovah would return at the time appointee, and Sarah should have a son. It was not so with Hagar and Ishmael, though God would make a nation of him because he was Abraham’s seed,
But there must be liberty in the house for all that are of God, and no entangling with the yoke of bondage. Every remnant of law, world, and flesh must be expelled, and what was of promise alone abide. But is it all ever thus judged till the day of “a great feast?” Then comes the decisive moment, and what is of the flesh persecute what is of the Spirit, and grace gives the Sarahs to speak out, and God will have it heard and acted on, though an Abraham may be grieved: but then, and not till then, is the bondmaid cast out with her son. The Sinai covenant that genders to bondage and her child after the flesh can be no longer tolerated in the household of faith.
The second quotation is in Rom. 9:77Neither, because they are the seed of Abraham, are they all children: but, In Isaac shall thy seed be called. (Romans 9:7). The apostle is combating the pretension of the Jews to enjoyment of the promises by natural or national descent, so as to exclude Gentiles. This he establishes in the most conclusive way by an appeal to Abraham's own seed, Ishmael. If the promise necessarily falls to the seed of Abraham as such, the Ishmaelites must be let in. As no Jew would allow of this, he must abandon his principle. It is a question of promise, not of fleshly descent but of His own sovereignty who had limited the call to Isaac. “In Isaac shall thy seed be called.” Sovereignty therefore is the only source of hope for Israel, which is reasoned out still more fully in the chapter, and applied to Jacob, to the exclusion of Esau, though of the same mother as well as father, and even twins. But the same sovereignty of God is shown to be the sole resource for Israel at Mount Sinai, when all else had been ruin for the people as a whole by their worship of the golden calf: so completely were they silenced on the score of their own righteousness. Driven thus from the ground of law, as well as of lineal descent, on what could they fall back? On the sovereign mercy of God. This alone did, or could, save a sinner or a sinful people in entire accordance with Ex. 33:1919And he said, I will make all my goodness pass before thee, and I will proclaim the name of the Lord before thee; and will be gracious to whom I will be gracious, and will show mercy on whom I will show mercy. (Exodus 33:19); but if they owned this, who were they to dispute that sovereignty calling Gentiles too, as indeed the prophets expressly declare that He would, when Israel became for a season Lo-ammi by their idolatry and their rejection of Messiah? But here we go beyond the passage which has given occasion to the apostolic argument. Still, looked at in the narrowest point of view, how fruitful is scripture, and how marvelously does He who wrote in the Old Testament use the facts and words in the New Testament! How self-evidently divine are both! Ishmael, like Israel after the flesh, cannot take the inheritance by law, but are cast out, though preserved of God.
It does not come within my present scope to dwell on God's dealings with Hagar, the comfort He gave her then and afterward as to Ishmael, or his subsequent history (vers. 14-21); though we may notice in passing that, as the bondmaid mother was an Egyptian, so the wife she took her son was out of the land of Egypt: law, flesh, and world go together.
But in the next section we see Abraham in his true place and dignity. “And it came to pass at that time, that Abimelech and Pichol the chief captain of his host spake unto Abraham, saying, God is with thee in all that thou doest: now therefore swear unto me here by God that thou wilt not deal falsely with me, nor with my son, nor with my son's son; but according to the kindness that I have done unto thee, thou shalt do unto me, and to the land wherein thou hast sojourned. And Abraham said, I will swear. And Abraham reproved Abimelech because of a well of water, which Abimelech's servants had violently taken away. And Abimelech said, I wot not who hath done this thing; neither didst thou tell me, neither yet heard I of it, but today. And Abraham took sheep and oxen, and gave them unto Abimelech; and both of them made a covenant. And Abraham set seven ewe lambs of the flock by themselves. And Abimelech said unto Abraham, What mean these seven ewe lambs which thou hast set by themselves? And he said, For these seven ewe lambs shalt thou take of my hand, that they may be a witness unto me that I have digged this well. Wherefore he called that place Beer-sheba; because there they sware both of them. Thus they made a covenant at Beer-sheba: then Abimelech rose up, and Phichol the chief captain of his host, and they returned into the land of the Philistines.” (Vers. 22-32.) The servant abides not in the house forever: Ishmael and his mother are dismissed. The son abides ever: Isaac is there, the heir of all. The Gentile king, who once inspired Abraham with guilty fear, and became the occasion of a foul snare, not only seeks favor of the father of the faithful but is himself reproved. The power of the world acknowledges God to be with Abraham, and asks for a covenant between them. (Compare Zech. 8:2323Thus saith the Lord of hosts; In those days it shall come to pass, that ten men shall take hold out of all languages of the nations, even shall take hold of the skirt of him that is a Jew, saying, We will go with you: for we have heard that God is with you. (Zechariah 8:23).) Earthly righteousness is now asserted, as before we saw heavenly long-suffering, save where a corresponding pledge of the coming kingdom came before us in Gen. 14, which concluded that series, as this concludes the later series. Here therefore the well of the oath is recovered and secured, and a grove or orchard is planted there, for the wilderness shall be glad, and the desert blossom as the lily; yea, there shall break out water and brooks, and there shall walk the redeemed. And Abraham “called there on the name of Jehovah, the everlasting God. And Abraham sojourned in the Philistines' land many days.” (Vers. 83, 34.) He is in type no longer the pilgrim, but the head of the nations, and heir of the world.