Contradiction with Genesis 17:21
Genesis 17:20 mentions God's promise to bless Ishmael and make him fruitful and multiply him exceedingly, having twelve princes come from him, and making him a great nation, while Genesis 17:21 specifies that God's covenant would only be established with Isaac, implying a differentiation in covenantal status between Ishmael and Isaac.
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.
Contradiction with Genesis 21:10
This verse records Sarah's demand to cast out Hagar and Ishmael, contradicting the notion of blessing and inclusion promised in Genesis 17:20, where God speaks of making a great nation of Ishmael.
Genesis 21:10: 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.
Contradiction with Galatians 4:30
Galatians speaks to the casting out of the bondwoman (Hagar) and her son (Ishmael), stating that the son of the bondwoman shall not be heir with the son of the freewoman (Isaac), which contradicts the blessing and nation-building promise mentioned in Genesis 17:20 for Ishmael.
Galatians 4:30: Nevertheless what saith the scripture? Cast out the bondwoman and her son: for the son of the bondwoman shall not be heir with the son of the freewoman.
Paradox #1
The potential contradiction or inconsistency with Genesis 17:20 might relate to the promise of blessings upon Ishmael and his descendants, which can be seen as inconsistent with the later biblical narrative that focuses primarily on Isaac and his descendants as the chosen line for God’s covenant. This may raise questions about why blessings are promised to both, but the covenant is established only with Isaac.
Paradox #2
Genesis 17:20 could present a moral conflict for some people because it involves God promising to bless Ishmael, even though Ishmael is not the chosen son through whom God's covenant is established. For some, this may seem inconsistent with the idea of a singular divine plan or favoritism towards one lineage, leading to questions about fairness and equal treatment.