'Minister to the Lord' in the Bible

‘This is the consecrated portion from the offerings by fire to the Lord that was designated for Aaron and his sons on the day he presented them to serve as priests to the Lord.

But as for us, the LORD is our God, and we have not forsaken him; and the priests, who minister to the LORD, are the sons of Aaron, and the Levites wait upon their business:

It shall be the holy portion of the land; it shall be for the priests, the ministers of the sanctuary, who come near to minister to the Lord, and it shall be a place for their houses and a holy place for the sanctuary.