“The actions performed by the priest in Mass are not ridiculous gestures, since they are done so as to represent something else. The priest in extending his arms signifies the outstretching of Christ’s arms upon the cross. He also lifts up his hands as he prays, to point out that his prayer is directed to God for the people, according to Lamentations 3:41: ‘Let us lift up our hearts with our hands to the Lord in the heavens’: and Exodus 17:11: ‘And when Moses lifted up his hands Israel overcame.’ That at times he joins his hands, and bows down, praying earnestly and humbly, denotes the humility and obedience of Christ, out of which He suffered. He closes his fingers, i.e. the thumb and first finger, after the consecration, because, with them, he had touched the consecrated body of Christ; so that if any particle cling to the fingers, it may not be scattered: and this belongs to the reverence for this sacrament.”    - St. Thomas Aquinas