The Lord’s Supper (LD 28; BC 35; Luke 22:19-20)

We follow the structure of the Heidelberg Catechism which progresses as the preaching of the gospel, then baptism, and now the Lord’s Supper.  We have argued from the previous Lord’s Day that infants are baptized because they are part of the covenant of grace so the sign of circumcision and baptism have a correlation to one another pointing to the same covenant of grace.  If this is true, then we do we not allow infants to come to the Lord’s table if Christ is celebrating the passover?  Or is the passover merely the opportunity to lay out the Lord’s Supper?  So, what is the Lord’s Supper?