Albert Barnes Commentary 1 Kings 8:3

"And all the elders of Israel came, and the priests took up the ark." — 1 Kings 8:3 (ASV)

In 2 Chronicles 5:4, the Levites took up the ark; and by the Law the ark was the special charge of the Kohathites (Numbers 3:31; Numbers 4:15). But all priests were Levites (Joshua 3:3), though not all Levites were priests. And as Joshua had done (Joshua 3:6; Joshua 6:6), so Solomon called upon the priests to bear the holy structure, allowing the other Levites only the inferior honor of helping to transport the tabernacle and the vessels of the sanctuary.