'Servant' in the Bible

The Revelation of Jesus Christ, which God gave him to show unto his servants, even the things which must shortly come to pass: and he sent and signified it by his angel unto his servant John;

And they sing the song of Moses the servant of God, and the song of the Lamb, saying, Great and marvellous are thy works, O Lord God, the Almighty; righteous and true are thy ways, thou King of the ages.