Faith is not immaterial. It is mediated through the senses–particularly hearing and sight. The ultimate object of this is the Incarnation. We have “seen and heard” the Word made flesh.
The original disciples did this through actually walking and talking with Jesus. We do it through the Church, especially the Bible and Sacraments–in which we participate by hearing and sight. Worship is the central act of the people of God, and as such it is a means of increasing our faith.
On this foundation our senses are transformed into instruments of witness and service–showing and telling others what we have seen and heard, that they may come to faith in Christ.