When he is present at the Eucharistic Celebration, a deacon should exercise his ministry, wearing sacred vestments. For the deacon Assists the priest and remains at his side; Ministers at the altar, with the chalice as well as the book; Proclaims the Gospel and, at the direction of the priest celebrant, may preach the homily (cf. no. 66); Guides the faithful by appropriate introductions and explanations, and announces the intentions of the Prayer of the Faithful; Assists the priest celebrant in distributing Communion, and purifies and arranges the sacred vessels; As needed, fulfills the duties of other ministers himself if none of them is present.
TheoFonsAd fontes fidei