Contradiction with Proverbs 30:5
Every word of God is pure, suggesting consistency, whereas Exodus 7:8 is part of a narrative showing God's power through signs.
Proverbs 30:5: Every word of God [is] pure: he [is] a shield unto them that put their trust in him. [pure: Heb. purified]
Contradiction with 1 Corinthians 14:33
For God is not the author of confusion, which contradicts the miraculous events causing confusion seen in Exodus 7:8.
1 Corinthians 14:33: For God is not [the author] of confusion, but of peace, as in all churches of the saints. [confusion: Gr. tumult, or, unquietness]
Contradiction with James 1:17
God is described as unchanging, while Exodus 7:8 introduces change with new signs and wonders.
James 1:17: Every good gift and every perfect gift is from above, and cometh down from the Father of lights, with whom is no variableness, neither shadow of turning.
Contradiction with Malachi 3:6
The LORD does not change, conflicting with the transformation of nature in Exodus 7:8.
Malachi 3:6: For I [am] the LORD, I change not; therefore ye sons of Jacob are not consumed.