'Slaves of God' in the Bible

No one can be a slave to two masters, for either he will hate one and love the other, or else he will be devoted to one and despise the other. You cannot be slaves of God and money.

But now, since you have been freed from sin and have become the slaves of God, the immediate result is consecration, and the final destiny is eternal life.

Live like free men, only do not make your freedom a pretext for doing evil, but live like slaves of God.