In the final lesson of the Renewing Your Mind series, Dr. J. V. Fesco turns his attention to the way God has marked His covenants with visible signs. He asks a question that has long intrigued scholars: why does the sign of the covenant move from circumcision to baptism when Christ comes?

How God Uses Visible Signs to Mark His Covenants

Dr. Fesco reminds listeners that covenant signs are more than symbolic gestures; they are “accompanying signs and incarnation, if you will, of His covenantal word.” He traces this pattern from the earliest act of creation—God’s command to light and the subsequent creation of light—to the covenant with Noah, where the rainbow becomes a tangible reminder of God’s promise to preserve creation. Each sign, he notes, is a physical act that invites people to experience the covenant with all their senses.

From Circumcision to Baptism: Why the Shift?

When the discussion turns to the transition from circumcision to baptism, Dr. Fesco cites Paul’s words in Galatians 2:17, where he says that the old signs are “a shadow of the things to come, but the substance belongs to Christ.” He explains that circumcision was the sign of the Abrahamic covenant, a marker of a regenerate heart and of the promise that the seed of the woman would crush the serpent. Baptism, in contrast, becomes the sign of the New Covenant, symbolizing the outpouring of the Holy Spirit and the new life believers receive through Christ’s death and resurrection.

What Baptism Reveals About the New Covenant

Dr. Fesco draws on John the Baptist’s proclamation that Jesus would baptize “with the Holy Spirit and fire.” He shows how baptism is not merely a ritual but a visible sign that Christ has poured the Spirit into the world, echoing the flood’s water that once covered creation. The Lord’s Supper is presented alongside baptism as the two sacraments that seal the covenant, confirming God’s promises in the person of Christ and the work of the Spirit.

To hear how these signs are woven together and what they reveal about God’s covenantal plan, listen to the full episode of Renewing Your Mind.