Christ assumed a true body of our nature. And because it is the special feature of friendship to live together with friends, He promises us His bodily presence as a reward... Yet meanwhile in our pilgrimage He does not deprive us of His bodily presence but unites us with Himself in this sacrament through the truth of His body and blood...Hence this sacrament is the sign of supreme charity [love], and the uplifter of our hope, from such familiar union of Christ with us.
--St. Thomas Aquinas