Contradiction with Proverbs 15:3
This verse says that the eyes of the LORD are in every place, beholding the evil and the good, whereas in 2 Samuel 18:24, the watchman goes up to the gate to behold from a specific location.
Proverbs 15:3: The eyes of the LORD [are] in every place, beholding the evil and the good.
Contradiction with Psalm 121:3-4
These verses emphasize that God neither slumbers nor sleeps, in contrast to the watchman in 2 Samuel 18:24 who must keep watch actively and may imply human limitations.
Psalm 121:3-4: He will not suffer thy foot to be moved: he that keepeth thee will not slumber.
Contradiction with Isaiah 40:28
This verse describes God as never weary and all-seeing, which contradicts with the human limitation of needing a watchman in 2 Samuel 18:24 to see the approaching man.
Isaiah 40:28: Hast thou not known? hast thou not heard, [that] the everlasting God, the LORD, the Creator of the ends of the earth, fainteth not, neither is weary? [there is] no searching of his understanding.