Gen. 12-20
Isaac stands in marked contrast with Abraham, though he and Jacob were “the fellow-heirs of the same promise.” But Abraham comes before us the unexpected object of sovereign grace. The tales, so plentiful among Jews and Mohametans, of preternatural ability and attainments of wisdom and goodness antecedent to his call, are altogether fabulous and excluded by scripture. All the more therefore did he suit divine election. No prophetic word hailed his birth like Noah's, whose father said, This same shall comfort us for our work and for the toil of our hands, because of the ground which Jehovah hath cursed. Yet no man was given to hold a place as “father of those that believe,” like Abraham, a headship of higher character than Adam's. But Isaac has the peculiarity of his own, however personally and in place overshadowed by his honored father, in that he was gradually introduced before his birth more frequently and signally than any, save that Son of Abraham, and Son of David Who was also Son of God as no one else ever could be, Isaac's great Antitype.
It may be of interest to draw out the evidence of this. In Gen. 12:7 “Jehovah appeared to Abram and said, To thy seed I will give this land; and there built he an altar to Jehovah who appeared to him.” Long before in Ur of the Chaldees had Jehovah said to Abraham, “Get thee (or, Go) out of thy country, and from thy kindred and from thy father's house, to the land that I will show thee. And I will make of thee a great nation, and I will bless thee and make thy name great; and thou shalt be a blessing. And I will bless them that bless thee, and curse him that curseth thee; and in thee shall all families of the earth be blessed” (Gen 12:1-3). Therein Abram at first failed, not quitting his father but following him to Haran, from which he did not emerge till his father's death (Acts 7:4).
Then and not before “Abram took Sarai his wife and Lot his brother's son, and all their possessions that they had acquired and the souls that they had got in Haran; and they went forth to go into the land of Canaan, and into the land of Canaan they came.” Obedience now had its perfect work, and its result accordingly. The renewed appearing of Jehovah was not only a call to separation, but to the walk of faith, a pilgrim and a worshipper in the land which was to be his only in hope. “By faith he became a sojourner in the land of promise as in [a land] not his own, dwelling in tents with Isaac and Jacob the fellow-heirs of the same promise; for he awaited the city that hath the foundations, whose designer and master-builder is God” (Heb. 11:9, 10). What was the possession of an earthly seat compared with this in heaven which dawned on his faith? Now he learns that Jehovah would give it to his “seed.” He worships and was content to be a stranger; and as he moved his tent elsewhere in the land, he built an altar to Jehovah and called on His name (8).
Still “seed” was vague, as it is explained in Rom. 9:7 and so appears also in John 8:33-39. But the time was not yet come. Abram failed in his new place, swerving from the revelation which had so happily wrought in his walk and worship. He goes down into Egypt for help under the strain of a famine in the land; and there is not a word of altar or tent. There he denies his wife, who was taken into the home of this world's prince, and got rich by it to his shame. Jehovah failed not, but plagued Pharaoh and extricated Sarai. This was not “all families of the earth blessed” in him: how could it be other than a curse when the depository of the blessing had left his true place with Jehovah and compromised his wife? Delivered by overruling mercy, he returns to the south, or Negeb, and thence as far as Bethel, “to the place where his tent had been at the beginning, between Bethel and Ai; to the place of the altar that he had made there at the first; and there Abram called on the name of Jehovah” (Gen. 13:3, 4). The humiliation before was blessed to one, whose first wrong step led to worse; but his heart turned to Him Who had rescued them, and he again regains his privilege without a fresh appearing to him. But in the strife between their respective herdmen that followed, Abram is as disinterested as his nephew betrays his worldly wisdom. And “Jehovah said to Abram, after that Lot had separated himself from him, Lift up now thine eyes and look from the place where thou art, northward and southward and eastward and westward; for all the land that thou seest will I give to thee and to thy seed forever. And I will make thy seed as the dust of the earth,” &c. (14-18). Lot has no title here. A fuller view of the land was given to him who looked above: it was secured forever to him and his. Again Abraham moves to Hebron and built there an altar to Jehovah. His worship rises afresh.
Next, after the wondrous episode of Abram's victory over the earthly potentates, who had punished their vassal kings and carried off Lot, and after the still more wondrous scene of the mysterious King-priest of the Most High God, we have (in a new series of Abram's history) the word of Jehovah coming in a vision, to assure him that not Eliezer, but “he that shall come forth out of thine own bowels shall be thine heir,” and like the unnumbered stars, “so shall thy seed be.” And he believed Jehovah, Who reckoned it to him as righteousness; of which the N. T. makes fruitful use. So it must be for the earthly seed, as well as the heavenly: flesh and blood cannot inherit the Kingdom of God. It is the earthly which is in view here; as this was what Abram sought, and God bound Himself by covenant based on death of victims, with prophecy and the limits of the land defined according to the Gentile races in present possession.
But if the son and heir was now defined to be Abram's, not so yet the mother. For in chap. 16 Sarah manifests the haste which is not of faith but the device of nature, to gain the blessing in its way to the sorrow of all and especially her own. This the apostle applies allegorically to Israel under law. In chap 17 Jehovah reveals Himself (not His gifts only) by the new name of El Shaddai (God Almighty), not His word in a vision, but God talking with him who has His covenant and the enlarged promise to be father of a multitude of nations, and kings to come out of him. Circumcision, death not of victims but of flesh, is imposed; and as Abram's name was now widened, so Sarai's was raised: Abram's son God would give of her. “And thou shalt call his name Isaac, and I will establish my covenant with him for an everlasting covenant to his seed after him” (19). Ishmael was not to be forgotten of God; but His covenant should be with Isaac, whom Sarah was to bear at this set time in the next year. Thus was the case made increasingly full and clear.
These preparative notices are crowned in chap. 18 where Jehovah appeared to Abraham by the terebinths of Mamre, and with two angels, who in human guise deigned to honor him as his guests. He thus emphasizes the importance to be attached to Isaac's birth, which even then Sarah laughs at as too wonderful. But the son and heir will surely come at the appointed time, and Jehovah personally announces it for the last time before it is accomplished. And we may note the proof He gives that He made Abraham His friend by telling him, not only the detail of what so intimately concerned himself and Sarah, but the judgment He was sending the angels to execute on the guilty cities of the plain. This draws out Abraham, not now to ask for himself, but to intercede, and Jehovah answered beyond his faith.
Yet Abraham failed once more after so signal a favor. How often it is so! Flesh is puffed up, not judged: we are off our guard, instead of watching to prayer. No flesh shall glory, but as it is written, He that glorieth, let him glory in the Lord. The unbelief of the believer led to deceit; and the sin of Abraham was worse now with Abimelech than long before with Pharaoh. He denied his wife's relationship, after Jehovah let him know the soon coming birth of the promised son by her. Yet though inexcusable and reproved by the Philistine king, God does not forget but maintains Abraham's relationship and makes Abimelech seek his prayers.