David was dressed as the high priest. This was quite unusual as the role of king was separate from the role of priests. In fact, in 1 Samuel 13:9-13 we see Saul not waiting for Samuel the priest to offer the burnt offerings, but rather doing it himself. Saul was severely rebuked for his actions. God’s people are not to over step their authority.
Yet here David is acting in the role of high priest, it seems that David had divine approval to do this. We read that David told the Levites, regarding the first attempt to bring the ark to Jerusalem, “We did not inquire of him about how to do it in the prescribed way” (v. 13). So presumably this being the second attempt, David did inquire of the Lord. God gave him the privilege of priest and king and enable him to bring the ark of the covenant back to the city.
It brings to mind the account of Melchizedek in Genesis 14:18 where Melchizedek is referred to as a king and priest. “Then Melchizedek king of Salem brought out bread and wine. He was priest of God Most High, and he blessed Abram . . . Then Abram gave him a tenth of everything” (Genesis 14:18-20). Salem was the original name of Jerusalem.
Only Melchizedek, David and Jesus, all kings of Jerusalem, shared the titles and privileges of king and priest at the same time.
As his children God gives us many privileges, but let’s not take them for granted.