Contradiction with Judges 4:14
Judges 4:14 immediately follows 4:13 and suggests that the Lord has already delivered Sisera into the hands of Israel, which could contradict the military advantage implied by Sisera's strength in Judges 4:13.
Judges 4:14: And Deborah said unto Barak, Up; for this [is] the day in which the LORD hath delivered Sisera into thine hand: is not the LORD gone out before thee? So Barak went down from mount Tabor, and ten thousand men after him.
Contradiction with Judges 4:15
Judges 4:15 describes how the Lord discomfited Sisera and his chariots, contradicting the power and threat of Sisera's army presented in Judges 4:13.
Judges 4:15: And the LORD discomfited Sisera, and all [his] chariots, and all [his] host, with the edge of the sword before Barak; so that Sisera lighted down off [his] chariot, and fled away on his feet.
Contradiction with Psalm 20:7
Psalm 20:7 contrasts trust in chariots and horses with trust in the Lord, which contradicts Sisera's reliance on his 900 chariots as seen in Judges 4:13.
Psalm 20:7: Some [trust] in chariots, and some in horses: but we will remember the name of the LORD our God.
Contradiction with Isaiah 31:1
Isaiah 31:1 warns against relying on chariots and horsemen, which contradicts Sisera's dependence on his vast number of iron chariots in Judges 4:13.
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!