(1) Ordinary Minister
The ordinary minister of solemn baptism is first the bishop and second the priest. By delegation, a deacon may confer the sacrament solemnly as an extraordinary minister. Bishops are said to be ordinary ministers because they are the successors of the Apostles who received directly the Divine command: "Go and teach all nations, baptizing them in the name of the Father and of the Son and of the Holy Ghost." Priests are also ordinary ministers because by their office and sacred orders they are pastors of souls and administrators of the sacraments, and hence the Florentine decree declares: "The minister of this Sacrament is the priest, to whom it belongs to administer baptism by reason of his office." As, however, bishops are superior to priests by the Divine law, the solemn administration of this sacrament was at one time reserved to the bishops, and a priest never administered this sacrament in the presence of a bishop unless commanded to do so, How ancient this discipline was, may be seen from Tertullian (De Bapt., xvii): "The right to confer baptism belongs to the chief priest who is the bishop, then to priests and deacons, but not without the authorization of the bishop." Ignatius (Ep. ad Smyr., viii): "It is not lawful to baptize or celebrate the agape without the bishop." St. Jerome (Contra Lucif., ix) witnesses to the same usage in his days: "Without chrism and the command of the bishop, neither priest nor deacon has the right of conferring baptism." Deacons are only extraordinary ministers of solemn baptism, as by their office they are assistants to the priestly order. St. Isidore of Seville (De Eccl, Off., ii, 25) says:
"It is plain that baptism is to be conferred by priests only, and it is not lawful even for deacons to administer it without permission of the bishop or priest." That deacons were, however, ministers of this sacrament by delegation is evident from the quotations adduced. In the service of ordination of a deacon, the bishop says to the candidate: "It behooves a deacon to minister at the altar, to baptize and to preach." Philip the deacon is mentioned in the Bible (Acts, viii) as conferring baptism, presumably by delegation of the Apostles. It is to be noted that though every priest, in virtue of his ordination is the ordinary minister of baptism, yet by ecclesiastical decrees he can not use this power licitly unless he has jurisdiction. Hence the Roman Ritual declares: The legitimate minister of baptism is the parish priest, or any other priest delegated by the parish priest or the bishop of the place." The Second Plenary Council of Baltimore adds:
"Priests are deserving of grave reprehension who rashly baptize infants of another parish or of another diocese." St. Alphonsus (n. 114) says that parents who bring their children for baptism without necessity to a priest other than their own pastor, are guilty of sin because they violate the rights of the parish priest. He adds, however, that other priests may baptize such children, if they have the permission, whether express, or tacit, or even reasonably presumed, of the proper pastor. Those who have no settled place of abode may be baptized by the pastor of any (catholic) church they choose.
http://www.newadvent.org/cathen/02258b.htm#XIII
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