'Serve' in the Bible

This is the portion of the anointing of Aaron and of the anointing of his sons, from Jehovah's offerings by fire, in the day when he presented them to serve Jehovah as priests,

And if thy brother grow poor beside thee, and be sold unto thee, thou shalt not compel him to serve as a bondservant:

as a hired servant, as a sojourner, shall he be with thee; until the year of jubilee shall he serve thee.