'Service of God' in the Bible

And they set the priests in their divisions, and the Levites in their courses, for the service of God, who is at Jerusalem; as it is written in the book of Moses.

Who are Israelites; to whom pertain the adoption, and the glory, and the covenants, and the giving of the law, and the service of God, and the promises;

Now when these things were thus ordained, the priests went always into the first tabernacle, accomplishing the service of God: