With whom did God establish His covenant, Ishmael or Isaac?

God established His covenant with Isaac, the son Sarah would bear at the set time, not Ishmael. Ishmael was nevertheless blessed, made fruitful, multiplied exceedingly, and promised twelve princes and a great nation. The covenant promise line continued through Isaac, then Jacob and the twelve tribes, as Scripture teaches.

Les explains from the passage that Ishmael was Abraham’s son, and God heard Abraham concerning him. God blessed Ishmael, made him fruitful, multiplied him exceedingly, gave him twelve princes, and made him a great nation. Les notes the Arabs outnumber the Jews fifty to one and have the oil, showing God blessed them. But God’s covenant was established with Isaac, whom Sarah would bear at the set time in the next year. Les ties this to Romans: not all Abraham’s children are children of the promise; only those through Isaac, Jacob, and the twelve tribes.

Genesis 17:21

But my covenant will I establish with Isaac, which Sarah shall bear unto thee at this set time in the next year.

With which son did God establish His covenant with Abraham?

God established His covenant with Abraham through Isaac, the son Sarah would bear at the set time. Scripture declares God's covenant would be established with Isaac, not Ishmael, though Ishmael also received promises of fruitfulness and a great nation, as recorded in Genesis 17.