Contradiction with Genesis 4:13-14
Cain expresses fear of being killed after being sentenced to wander the earth, whereas in Genesis 21:18, God assures Hagar of Ishmael's protection.
Genesis 4:13-14: And Cain said unto the LORD, My punishment [is] greater than I can bear. [My...: or, Mine iniquity is greater than that it may be forgiven]
Contradiction with Genesis 19:24
God destroys Sodom and Gomorrah with fire and brimstone, conflicting with Genesis 21:18 where there is a promise of protection.
Genesis 19:24: Then the LORD rained upon Sodom and upon Gomorrah brimstone and fire from the LORD out of heaven;
Contradiction with Exodus 12:29
The Lord smites all the firstborn in Egypt, which contrasts with Genesis 21:18 where God promises life and future to Ishmael.
Exodus 12:29: And it came to pass, that at midnight the LORD smote all the firstborn in the land of Egypt, from the firstborn of Pharaoh that sat on his throne unto the firstborn of the captive that [was] in the dungeon; and all the firstborn of cattle. [dungeon: Heb. house of the pit]
Contradiction with Job 1:18-19
Job's children are killed suddenly, whereas Genesis 21:18 promises survival and a future for Ishmael.
Job 1:18-19: While he [was] yet speaking, there came also another, and said, Thy sons and thy daughters [were] eating and drinking wine in their eldest brother's house:
Contradiction with 2 Kings 2:23-24
Elisha curses the mocking children; they're killed by bears, contradicting Genesis 21:18 where divine assurance of life is given.
2 Kings 2:23-24: And he went up from thence unto Bethel: and as he was going up by the way, there came forth little children out of the city, and mocked him, and said unto him, Go up, thou bald head; go up, thou bald head.
Contradiction with Psalm 109:9
This verse calls for orphans, whereas Genesis 21:18 involves a promise of survival and posterity.
Psalm 109:9: Let his children be fatherless, and his wife a widow.
Contradiction with Isaiah 5:25
God's anger leads to destruction, differing from Genesis 21:18 where God promises safeguarding Ishmael.
Isaiah 5:25: Therefore is the anger of the LORD kindled against his people, and he hath stretched forth his hand against them, and hath smitten them: and the hills did tremble, and their carcases [were] torn in the midst of the streets. For all this his anger is not turned away, but his hand [is] stretched out still. [torn: or, as dung]
Contradiction with Jeremiah 6:11-12
God's fury is poured out on children, contradicting Genesis 21:18's promise of life and protection.
Jeremiah 6:11-12: Therefore I am full of the fury of the LORD; I am weary with holding in: I will pour it out upon the children abroad, and upon the assembly of young men together: for even the husband with the wife shall be taken, the aged with [him that is] full of days.
Contradiction with Ezekiel 9:6
God commands to slay the old and young, which contrasts with the life assurance in Genesis 21:18.
Ezekiel 9:6: Slay utterly old [and] young, both maids, and little children, and women: but come not near any man upon whom [is] the mark; and begin at my sanctuary. Then they began at the ancient men which [were] before the house. [utterly: Heb. to destruction]
Contradiction with Matthew 2:16
Herod orders the massacre of infants, conflicting with Genesis 21:18 where there is a divine safeguard for the child Ishmael.
Matthew 2:16: Then was fulfilled that which was spoken by Jeremy the prophet, saying,
Contradiction with Acts 12:23
God immediately smites Herod with worms for not giving glory, yet Genesis 21:18 shows God proactively preserving life.
Acts 12:23: And immediately the angel of the Lord smote him, because he gave not God the glory: and he was eaten of worms, and gave up the ghost.