1 Chronicles 15:21
And Mattithiah, and Elipheleh, and Mikneiah, and Obed-edom, and Jeiel, and Azaziah, with harps on the Sheminith to excel. And Mattithiah, and Elipheleh, and Mikneiah, and Obed-edom, and Jeiel, and Azaziah, with harps on the Sheminith to excel.
The verse is part of the account of David's plan to bring the ark of God to Jerusalem, listing musicians assigned to play harps during that event. It belongs to the account of bringing the ark from Kirjath-jearim to Jerusalem. It belongs to the account of bringing the ark to Jerusalem and placing it in a tent he had set up for it.
The ark was brought according to God's appointed order after its earlier transport on a cart had led to Uzzah's death. The Levites were to carry it on their shoulders, and David acknowledged that the earlier failure to follow this order had brought judgment. In that corrected order, the verse names Mattithiah, Elipheleh, Mikneiah, Obed-edom, Jeiel, and Azaziah as Levite musicians assigned to play harps on the Sheminith as part of the sacred procession and worship.
The verse shows that David organized instrumental music as part of religious service and that these musicians were to play skillfully, to excel. The phrase on the Sheminith denotes the manner of harp playing in that service. It is an ancient musical term whose precise meaning is uncertain.