Can. 840 The sacraments of the New Testament were instituted by Christ the Lord and entrusted to the Church. As actions of Christ and the Church, they are signs and means which express and strengthen the faith, render worship to God, and effect the sanctification of humanity and thus contribute in the greatest way to establish, strengthen, and manifest ecclesiastical communion. Accordingly, in the celebration of the sacraments the sacred ministers and the other members of the Christian faithful must use the greatest veneration and necessary diligence.
Can. 841 Since the sacraments are the same for the whole Church and belong to the divine deposit, it is only for the supreme authority of the Church to approve or define the requirements for their validity; it is for the same or another competent authority according to the norm of can. 838 §§3 and 4 to decide what pertains to their licit celebration, administration, and reception and to the order to be observed in their celebration.
Can. 842 §1. A person who has not received baptism cannot be admitted validly to the other sacraments.
§2. The sacraments of baptism, confirmation, and the Most Holy Eucharist are interrelated in such a way that they are required for full Christian initiation.
Can. 843 §1. Sacred ministers cannot deny the sacraments to those who seek them at appropriate times, are properly disposed, and are not prohibited by law from receiving them.
§2. Pastors of souls and other members of the Christian faithful, according to their respective ecclesiastical function, have the duty to take care that those who seek the sacraments are prepared to receive them by proper evangelization and catechetical instruction, attentive to the norms issued by competent authority.
Can. 844 §1. Catholic ministers administer the sacraments licitly to Catholic members of the Christian faithful alone, who likewise receive them licitly from Catholic ministers alone, without prejudice to the prescripts of §§2, 3, and 4 of this canon, and can. 861, §2.
§2. Whenever necessity requires it or true spiritual advantage suggests it, and provided that danger of error or of indifferentism is avoided, the Christian faithful for whom it is physically or morally impossible to approach a Catholic minister are permitted to receive the sacraments of penance, Eucharist, and anointing of the sick from non-Catholic ministers in whose Churches these sacraments are valid.
§3. Catholic ministers administer the sacraments of penance, Eucharist, and anointing of the sick licitly to members of Eastern Churches which do not have full communion with the Catholic Church if they seek such on their own accord and are properly disposed. This is also valid for members of other Churches which in the judgment of the Apostolic See are in the same condition in regard to the sacraments as these Eastern Churches.
§4. If the danger of death is present or if, in the judgment of the diocesan bishop or conference of bishops, some other grave necessity urges it, Catholic ministers administer these same sacraments licitly also to other Christians not having full communion with the Catholic Church, who cannot approach a minister of their own community and who seek such on their own accord, provided that they manifest Catholic faith in respect to these sacraments and are properly disposed.
§5. For the cases mentioned in §§2, 3, and 4, the diocesan bishop or conference of bishops is not to issue general norms except after consultation at least with the local competent authority of the interested non-Catholic Church or community.
Can. 845 §1. Since the sacraments of baptism, confirmation, and orders imprint a character, they cannot be repeated.
§2. If after completing a diligent inquiry a prudent doubt still exists whether the sacraments mentioned in §1 were actually or validly conferred, they are to be conferred conditionally.
Can. 846 §1. In celebrating the sacraments the liturgical books approved by competent authority are to be observed faithfully; accordingly, no one is to add, omit, or alter anything in them on one’s own authority.
§2. The minister is to celebrate the sacraments according to the minister’s own rite.
Can. 847 §1. In administering the sacraments in which holy oils must be used, the minister must use oils pressed from olives or other plants and, without prejudice to the prescript of can. 999, n. 2, consecrated or blessed recently by a bishop; he is not to use old oils unless it is necessary.
§2. The pastor is to obtain the holy oils from his own bishop and is to preserve them diligently with proper care.
Can. 848 The minister is to seek nothing for the administration of the sacraments beyond the offerings defined by competent authority, always taking care that the needy are not deprived of the assistance of the sacraments because of poverty.