"The canon law of the Catholic Church is the system of laws and legal principles made and enforced by the hierarchical authorities of the Church to regulate its external organization and government and to order and direct the activities of Catholics toward the mission of the Church"
"Art. 1.
THE MINISTER OF THE MOST HOLY EUCHARIST
Can. 900 1. The minister who is able to confect
the sacrament of the Eucharist in the person of Christ is a validly ordained
priest alone.
§2. A priest not impeded by canon law celebrates the
Eucharist licitly; the provisions of the following canons are to be observed.
Can. 901 A priest is free to apply the Mass for
anyone, living or dead.
Can. 902 Unless the welfare of the Christian
faithful requires or suggests otherwise, priests can concelebrate the
Eucharist. They are completely free to celebrate the Eucharist individually,
however, but not while a concelebration is taking place in the same church or
oratory.
Can. 903 A priest is to be permitted to celebrate
even if the rector of the church does not know him, provided that either he
presents a letter of introduction from his ordinary or superior, issued at
least within the year, or it can be judged prudently that he is not impeded
from celebrating.
Can. 904 Remembering always that in the mystery of
the eucharistic sacrifice the work of redemption is exercised continually,
priests are to celebrate frequently; indeed, daily celebration is recommended
earnestly since, even if the faithful cannot be present, it is the act of
Christ and the Church in which priests fulfill their principal function.
Can. 905 1. A priest is not permitted to
celebrate the Eucharist more than once a day except in cases where the law
permits him to celebrate or concelebrate more than once on the same day.
§2. If there is a shortage of priests, the local
ordinary can allow priests to celebrate twice a day for a just cause, or if
pastoral necessity requires it, even three times on Sundays and holy days of
obligation.
Can. 906 Except for a just and reasonable cause, a
priest is not to celebrate the eucharistic sacrifice without the participation
of at least some member of the faithful.
Can. 907 In the eucharistic celebration deacons
and lay persons are not permitted to offer prayers, especially the eucharistic
prayer, or to perform actions which are proper to the celebrating priest.
Can. 908 Catholic priests are forbidden to
concelebrate the Eucharist with priests or ministers of Churches or ecclesial
communities which do not have full communion with the Catholic Church.
Can. 909 A priest is not to neglect to prepare
himself properly through prayer for the celebration of the eucharistic
sacrifice and to offer thanks to God at its completion.
Can. 910 1. The ordinary minister of holy
communion is a bishop, presbyter, or deacon.
§2. The extraordinary minister of holy communion is
an acolyte or another member of the Christian faithful designated according to
the norm of can. 230, §3.
Can. 911 1. The pastor, parochial vicars,
chaplains, and, with regard to all those dwelling in the house, the superior of
a community in clerical religious institutes and societies of apostolic life
have the duty and right of bringing the Most Holy Eucharist as Viaticum to the
sick.
2. In the case of necessity or with at least the
presumed permission of the pastor, chaplain, or superior, who must be notified
afterwards, any priest or other minister of holy communion must do this."