a slave of righteousness

“Do you not know that to whom you present yourselves slaves to obey, you are that one’s slaves whom you obey, whether of sin leading to death, or of obedience leading to righteousness?
“But God be thanked that though you were slaves of sin, yet you obeyed from the heart that form of doctrine to which you were delivered.
“And having been set free from sin, you became slaves of righteousness” (Romans 6:16-18).
 
The Apostle Paul here describes an action the Romans have taken so that they could move from one state to another: they moved from being a slave of sin to a slave of righteousness.
 
To accomplish this move, the Romans have sincerely obeyed what Paul calls “the form of doctrine to which you were delivered.” That form is a reenactment of Jesus’ death on the cross, His burial in the tomb, and His resurrection from the tomb. Baptism is the reenactment to which he is referring.
 
We become dead to our past sins when we are immersed in the watery grave and then are brought up out of the watery grave. This action completes our obedience to the gospel, and we are now a servant of righteousness, which is the same as being a servant of Jesus.