Contradiction with Isaiah 31:1
Warns against seeking help from Egypt, contradicting Isaiah 36:8 where an alliance is seemingly encouraged.
Isaiah 31:1: Woe to them that go down to Egypt for help; and stay on horses, and trust in chariots, because [they are] many; and in horsemen, because they are very strong; but they look not unto the Holy One of Israel, neither seek the LORD!
Contradiction with Isaiah 30:3
States that trusting in Egypt will lead to shame, contrasting with the implication in Isaiah 36:8 of relying on Egypt.
Isaiah 30:3: Therefore shall the strength of Pharaoh be your shame, and the trust in the shadow of Egypt [your] confusion.
Contradiction with Isaiah 20:5
Describes how those who rely on Egypt will be dismayed and ashamed, opposing Isaiah 36:8's suggestion of allying with Egypt.
Isaiah 20:5: And they shall be afraid and ashamed of Ethiopia their expectation, and of Egypt their glory.
Contradiction with Isaiah 30:7
Declares Egypt's help is worthless, contradicting the offer in Isaiah 36:8.
Isaiah 30:7: For the Egyptians shall help in vain, and to no purpose: therefore have I cried concerning this, Their strength [is] to sit still. [concerning...: or, to her]
Contradiction with Jeremiah 37:7-8
Foretells the failure of Egyptian aid, which opposes the trust in Egypt seen in Isaiah 36:8.
Jeremiah 37:7-8: Thus saith the LORD, the God of Israel; Thus shall ye say to the king of Judah, that sent you unto me to enquire of me; Behold, Pharaoh's army, which is come forth to help you, shall return to Egypt into their own land.