Paul tethers this part of his argument to the analogy of baptism. We are incorporated into the death and resurrection of Christ.

Your physical baptism is a tangible picture of what spiritually (but really!) happened the moment you trusted Jesus.

You see, the act of being dunked underwater resembles dying with Christ, being buried in the tomb with him. But of course, the act of baptism doesn’t end there, because Jesus’s story didn’t and neither does yours! The act of being brought up from the water resembles the new life of resurrection. Yes, what happened to Jesus on that first Easter will happen to you too! And in some sense, it already has. Not that your body has been resurrected to immortality (that is for a future day). But your inner-self (call it your spirit or your soul) has already been elevated to a new form of life, following the pattern of Christ’s resurrection and stamped with the authenticity of the presence of the Holy Spirit.