In the liturgy of the Church we approach that perfect harmony between the outward and the inward. We celebrate Redemption, which has begun to knit things back together. We anticipate the final Redemption of all things when that restoration will be completed. We recall the Incarnation, in which we find the perfect uniting of form and matter, that is, of perfect wholeness and purity with human flesh. We see in the Second Adam the perfection that was to have been exhibited in the first.
The ceremonies of the liturgy answer to all of this. For in the liturgy we step into redemption, in faith, and bespeak the perfect uniting of the outer and the inner that will be unfurled in the new heavens and the new earth. We renounce the divided world where body wars against heart and where gesture struggles with thought. By enacting what is true, we learn what is true. By bowing our heads as well as our hearts, we testify to the restored seamlessness of outer and inner. By bowing with the knee we teach our reluctant hearts to bow. By making the sign of the cross with our hands we signal to heaven, earth, hell, and to our innermost beings that we are indeed under this sign — that we are crucified with Christ. No longer do we refuse the outer gesture in the name of the inner faith. Buddhism, Platonism, and Manichaeanism may do so, but Christian faith cries out to be shaped.
-from Evangelical is Not Enough: Worship of God in Liturgy and Sacrament, by Thomas Howard