It is part of the virtue of religion to show reverence to God, to respect his name, and to honor everything connected with him: persons, places, or objects…Catholic faith in the Holy Eucharist is the foundation for reverence for this sacrifice and sacrament…The individual Catholic who receives Jesus in the sacrament of the Holy Eucharist shows reverence in many ways. The most important proof of a communicant’s reverence is given by his being in a state of grace. Any Catholic who is unfortunately in the state of mortal sin is bound to go to confession and receive absolution before approaching the Eucharistic table…We also show reverence by the way we receive Holy Communion, kneeling, standing, on the tongue or in the hand. Even how we dress, how we walk, and how we share in the congregation’s acts of singing, standing, sitting, listening, and kneeling can show our faith. Personal prayer also prepares us for proper participation in the liturgy and helps us to savor its fruits…According to personal devotion, a communicant may wish to kneel or sit in quiet thanksgiving after Communion…Thanksgiving after Mass has traditionally been greatly esteemed in the Church for both the priest and the lay faithful…Reverence is not automatic, It has to be nurtured, to be built up, to be kept up.
Francis Cardinal Arinze: Celebrating the Holy Eucharist. pp. 32-39