THE MOST HOLY EUCHARIST (The Code of Canon Law)
Can. 897 The most August sacrament is the Most Holy Eucharist in which Christ the Lord himself is contained, offered, and received and by which the Church continually lives and grows. The eucharistic sacrifice, the memorial of the death and resurrection of the Lord, in which the sacrifice of the cross is perpetuated through the ages is the summit and source of all worship and Christian life, which signifies and effects the unity of the People of God and brings about the building up of the body of Christ. Indeed, the other sacraments and all the ecclesiastical works of the apostolate are closely connected with the Most Holy Eucharist and ordered to it.
Can. 898 The Christian faithful are to hold the Most Holy Eucharist in highest honor, taking an active part in the celebration of the most august sacrifice, receiving this sacrament most devoutly and frequently, and worshiping it with the highest adoration. In explaining the doctrine about this sacrament, pastors of souls are to teach the faithful diligently about this obligation.
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. 937 Unless there is a grave reason to the contrary, the church in which the Most Holy Eucharist is reserved is to be open to the faithful for at least some hours every day so that they can pray before the Most Blessed Sacrament.