It is not medieval, but biblical for a Christian to realize when considering the sacrament, that we are given the bodily Self of the Lord... that we are given the possibility of addressing ourselves in faith and love, in adoration and acceptance, to that Lord bodily present to us... It is actually plain heresy to say (in theory and hence in practice) that Jesus Christ in the Sacrament of the altar is not to be honored with an external cult of adoration... that exposition is to be rejected.

The Christian Commitment
Karl Rahner, S.J.