'Ministering' in the Bible

"But as for us, Yahweh is our God, and we have not forsaken him; and [we have] priests ministering to Yahweh, the sons of Aaron, and the Levites in their work:

It happened, when Jehu was executing judgment on the house of Ahab, that he found the princes of Judah, and the sons of the brothers of Ahaziah, ministering to Ahaziah, and killed them.