Who did God promise the line of promise would come through, Isaac or Ishmael?
God promised that the line of promise would come through Isaac, not Ishmael. The promise passed through Abraham and Isaac to the next son of promise, showing God's elective purpose. Ishmael was excluded from this particular promised lineage. Scripture later ties the promise to Isaac's descendants, including Jacob rather than Esau.
Les explains that God made the promise that through Abraham and Isaac, not Ishmael, the next son of promise would come. The context then moves to Rebecca conceiving by Isaac, with twins Esau and Jacob in her womb before they were born or had done anything good or evil. This was so the purpose of God according to election might stand, not of works or what man deserves, but of Him who calls—the sovereign God. Les also illustrates the "whosoever will" door and then being chosen from before the foundation of the world.
Neither, because they are the seed of Abraham, are they all children: but, In Isaac shall thy seed be called.
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