Buried with Christ
"Therefore we are buried with him by baptism into death, that like as Christ was raised up from the dead by the glory of the Father, even so we also should walk in newness of life." (Romans 6:4)
And finally, the resurrection, demonstrating Christ's eternal victory over sin and death, and, in the case of the believer, the beginning of the new life in Christ. The same truth appears again in Colossians 2:12: "Buried with him in baptism, wherein also ye are risen with him through the faith of the operation of God, who hath raised him from the dead." Although these are the only New Testament passages where the doctrinal implications of Christ's burial are specifically mentioned, the spiritual truths taught thereby permeate all the Scriptures.
If our old bodies of sin are--at least positionally--already in the grave, then it is altogether grotesque for them still to be walking around in sin. "For if we have been planted together in the likeness of his death, we shall be also in the likeness of his resurrection" (Romans 6:5). We shall (not "should," as misleadingly rendered in our text) walk in newness of life, triumphant daily over sin through the implanted resurrection life of our victorious Savior.