From the Eucharist to the Holy Spirit, and we have it on the authority of two Doctors, Ephrem and John:
17. Through our communion in his body and blood, Christ also grants us his Spirit. Saint Ephrem writes: “He called the bread his living body and he filled it with himself and his Spirit… He who eats it with faith, eats Fire and Spirit… Take and eat this, all of you, and eat with it the Holy Spirit. For it is truly my body and whoever eats it will have eternal life”. (Sermo IV in Hebdomadam Sanctam: CSCO 413/Syr. 182, 55.) The Church implores this divine Gift, the source of every other gift, in the Eucharistic epiclesis. In the Divine Liturgy of Saint John Chrysostom, for example, we find the prayer: “We beseech, implore and beg you: send your Holy Spirit upon us all and upon these gifts… that those who partake of them may be purified in soul, receive the forgiveness of their sins, and share in the Holy Spirit”. (Anaphora.) And in the Roman Missal the celebrant prays: “grant that we who are nourished by his body and blood may be filled with his Holy Spirit, and become one body, one spirit in Christ”. (Eucharistic Prayer III.) Thus by the gift of his body and blood Christ increases within us the gift of his Spirit, already poured out in Baptism and bestowed as a “seal” in the sacrament of Confirmation.
And so the Holy Spirit, called down during the epiclesis of the Eucharistic Prayer, is a gift while we celebrate the Eucharist as well.