It is often misunderstood what it means to be regenerated and Born Again into the Body of Christ. Usually the common idea is that you are now free. Which is correct that you are now freed to fight against your old man/woman and to conquer any sin in your life. However, you are not free as most people think of it as in no longer being a slave.
Instead, you have switched Masters from Sin, the Flesh and the Devil to God. He is our new master and the one we had in Adam before The Fall in the Garden of Eden. Word often translated as Bond servant of Christ is in fact the Greek word for slave. We are slaves to Christ and thus no longer a Child of Wrath enslaved to Sin and Satan.
There is no such thing as serving no spiritual master you either are a slave of God or a Slave to Satan. A Slave in the Godly Kingdom or a slave to the Kingdom of Darkness of Satan and his minions. Only God can through His Regeneration and New Creation through being Born Again switch you out of the Kingdom of Darkness and bring you to be his Slave in the Kingdom of God.
https://biblehub.com/greek/1401.htm
https://www.recorder.com/A-history-of-slavery-41316876
