2:11 Christ performed a spiritual circumcision: Spiritual conversion to Christ is the Christian counterpart to physical circumcision. • the cutting away of your sinful nature (literally the cutting away of the body of the flesh): Just as Jewish boys have the flesh of their foreskin cut off to mark their initiation into the people of God, so believers have metaphorical flesh (translated sinful nature) cut off when they come to Christ.

2:12 you were buried with Christ when you were baptized: As in a roughly parallel passage (Rom 6:3-6), Paul assumes a strong identity between believers and Christ. In God’s sight, we really were with Christ when he was buried and raised, so we experience the benefits of what Christ did for us. Paul can link that identification with Christ to baptism because water baptism was so closely related to conversion in the early church.

2:15 He shamed them publicly by his victory (literally he led [them] in triumphal procession): The Roman army would celebrate a great victory with a triumphal procession. The victorious Roman general would lead the humiliated captives from his campaign into the conquered city. The image vividly captures the glorious victory that God, through the cross of Christ, has won over all hostile spiritual powers (see also Eph 4:7-11).