Contradiction with Numbers 18:1-7
Contradicts by stating the responsibilities for the sanctuary rest solely with Aaron and his descendants.
Numbers 18:1-7: And the LORD said unto Aaron, Thou and thy sons and thy father's house with thee shall bear the iniquity of the sanctuary: and thou and thy sons with thee shall bear the iniquity of your priesthood.
Contradiction with Hebrews 9:6-7
Contradicts by emphasizing the high priest's role in handling sacred duties, implicitly different from the role of Levite porters.
Hebrews 9:6-7: Now when these things were thus ordained, the priests went always into the first tabernacle, accomplishing the service [of God].
Contradiction with 2 Chronicles 23:19
Contradicts by assigning gatekeeping duties to the Levites in a context of different authority than outlined in 1 Chronicles 9:26.
2 Chronicles 23:19: And he set the porters at the gates of the house of the LORD, that none [which was] unclean in any thing should enter in.