Romans 6.4

Therefore we have been buried with him by baptism into death, so that, just as Christ was raised from the dead by the glory of the Father, so we too might walk in newness of life.

Paul's insistence we are saved by Grace through Faith, rather than by Works of the Law, laid him open to the charge he was saying it's OK to sin. Paul says this is nonsense ["By no means!"].

Our Baptism means, by Christ's death and resurrection, Sin and Death have been overcome - the meaning of his statement we are "dead to Sin."

He does not mean we will never, ever sin once baptized - we are human. What he means is Sin and Death no longer have ultimate power over us. We will be united to Christ in a resurrection like his, and this glorious resurrection, which will happen in the future, is partially available to us now - though then we will see face-to-face and now we look into a mirror darkly.

Our job in the meantime is to be "alive to God in Christ Jesus," to "present [ourselves] to God as those who have been brought from death to life," to "present [our] members [all our faculties and functions] as instruments of righteousness," and do our best to work toward the coming Kingdom "on earth as it is in heaven."