'Minister' in the Bible

Also the sons of the alien, that join themselves to Jehovah, to minister unto him and to love the name of Jehovah, to be his servants, every one that keepeth the sabbath from profaning it, and holdeth fast to my covenant;

And the sons of the alien shall build up thy walls, and their kings shall minister unto thee. For in my wrath I smote thee, but in my favour have I had mercy on thee.