Contradiction with Deuteronomy 7:1
This verse states that God will clear away many nations before the Israelites, including giants, which contrasts Nehemiah 9:23 where the children of Israel were to possess the land, implying different timing and involvement.
Deuteronomy 7:1: When the LORD thy God shall bring thee into the land whither thou goest to possess it, and hath cast out many nations before thee, the Hittites, and the Girgashites, and the Amorites, and the Canaanites, and the Perizzites, and the Hivites, and the Jebusites, seven nations greater and mightier than thou;
Contradiction with Numbers 13:33
Describes the Israelites seeing themselves as grasshoppers in comparison to the giants, contradicting the notion of conquering the land as mentioned in Nehemiah 9:23 without fear.
Numbers 13:33: And there we saw the giants, the sons of Anak, [which come] of the giants: and we were in our own sight as grasshoppers, and so we were in their sight.
Contradiction with Joshua 17:12-13
Notes that the children of Manasseh could not drive out the Canaanites entirely, contradicting Nehemiah 9:23's implication of complete possession of the land.
Joshua 17:12-13: Yet the children of Manasseh could not drive out [the inhabitants of] those cities; but the Canaanites would dwell in that land.