Who did Ishmael marry and what did that show about the two lines?
Ishmael married an Egyptian woman, while Isaac's wife came from relatives in Syria. That contrast showed the two lines had totally divergent genealogies and, spiritually speaking, no union existed between Ishmael and Isaac, marking a clear separation between the bondwoman's line and the promised spiritual line.
Les teaches that the split was absolute. Sarah told Abraham to cast out the bondwoman and her son because Ishmael was taunting Isaac, and the point was not to move them nearby but to put them out of sight. Although Isaac and Ishmael later came together for their parents' funeral, spiritually there was no union between them. Isaac continued in the spiritual line and took a wife from Syria where the relatives were; Ishmael, by contrast, married an Egyptian, showing a total divergence of the two genealogies. Les stresses that this was not merely a mother's thought but the Word of God.
More Questions
How did the lines of Isaac and Ishmael diverge after they separated?
After the split, Isaac continued in the spiritual line and took a wife from his relatives in Syria, while Ishmael married an Egyptian, so the genealogies of the two young men diverged completely.