One element not entirely clear in the Novus Ordo Missae (New Order of Mass promulgated after Vatican II) is a direct invitation to the faithful to come and receive the Body and Blood of the Lord. There is an element of indirect invitation woven into the liturgy that is generally seen as an invitation to Eucharistic participation:
Priest: Behold the Lamb of God,
behold him who takes away the sins of the world.
Blessed are those called to the supper of the Lamb.
All: Lord, I am not worthy
that you should enter under my roof,
but only say the word
and my soul shall be healed.
Yet it strikes me that something more should have been added after the portion quoted above ... namely a direct invitation to the faithful to come to the Supper of the Lord.
I suspect that my sensitivity to this is entirely because of my Anglican and Episcopalian background, for many of the Anglican liturgies included elements of direct invitation to come to the Altar to receive the Body and Blood of the Lord or the invitation was couched in terms of Confession in proper approach to the Eucharistic Lord.
In the Church of England's Alternative Services Second Series we first saw the following form of invitation, and it remains my favourite of the shorter forms:
In one of the Eucharistic liturgies of the Old Catholics (Utrecht) in Switzerland, the people are invited to Holy Communion with the words (in translation) "Come, for all is prepared for you." I have found these words a profoundly personalising moment in which the Eucharistic sacrifice becomes connected to the personal invitation to come to the celestial marriage banquet of the Lamb. Woe betide the soul who says, "I cannot come."
Come, for all is prepared for you!