Paul is thinking of the cross and empty tomb, but the liturgical calendar places us at the beginning of Jesus’ ministry, not the end: Jesus standing waist deep in the Jordan River.
Not only does God reveal the identity of Jesus in this season through what we see and hear Jesus doing and saying, but God also reveals His gracious will through Jesus despite what we see and hear.
Throughout the Scriptures, God puts "signs" or "seals" upon people. Often these are placed upon the forehead. How do all these connected stories take us from the mark of Cain, to the Exodus, to the cross, and finally to baptism?
Without the sacraments, God’s grace is simply an artifact behind a glass-case in a museum. We might be able to describe and even admire it, but we never get firsthand access to it.