'Minister' in the Bible

This is the portion of the anointing of Aaron, and of the anointing of his sons, out of the offerings of the LORD made by fire, in the day when he presented them to minister unto the LORD in the priest's office;

And the priest, whom he shall anoint, and whom he shall consecrate to minister in the priest's office in his father's stead, shall make the atonement, and shall put on the linen clothes, even the holy garments: