be a change of form to say, "I baptize myself":
consequently no one can baptize himself. For this reason did Christ
choose to be baptized by John (Extra, De Baptismo et ejus effectu,
cap. Debitum).

Reply Obj. 5: Although Christ's Passion is the principal cause as
compared to the minister, yet it is an instrumental cause as compared
to the Blessed Trinity. For this reason the Trinity is mentioned
rather than Christ's Passion.

Reply Obj. 6: Although there are three personal names of the three
Persons, there is but one essential name. Now the Divine power which
works in Baptism, pertains to the Essence; and therefore we say, "in
the name," and not, "in the names."

Reply Obj. 7: Just as water is used in Baptism, because it is more
commonly employed in washing, so for the purpose of designating the
three Persons, in the form of Baptism, those names are chosen, which
are generally used, in a particular language, to signify the Persons.
Nor is the sacrament valid if conferred in any other names.
_______________________

SIXTH ARTICLE [III, Q. 66, Art. 6]

Whether Baptism Can Be Conferred in the Name of Christ?

Objection 1: It seems that Baptism can be conferred in the name of
Christ. For just as there is "one Faith," so is there "one Baptism"
(Eph. 4:5). But it is related (Acts 8:12) that "in the name of Jesus
Christ they were baptized, both men and women." Therefore now also
can Baptism be conferred in the name of Christ.

Obj. 2: Further, Ambrose says (De Spir. Sanct. i): "If you mention
Christ, you designate both the Father by Whom He was anointed, and
the Son Himself, Who was anointed, and the Holy Ghost with Whom He
was anointed." But Baptism can be conferred in the name of the
Trinity: therefore also in the name of Christ.

Obj. 3: Further, Pope Nicholas I, answering questions put to him by
the Bulgars, said: "Those who have been baptized in the name of the
Trinity, or only in the name of Christ, as we read in the Acts of the
Apostles (it is all the same, as Blessed Ambrose saith), must not be
rebaptized." But they would be baptized again if they had not been
validly baptized with that form. Therefore Baptism can be celebrated
in the name of Christ by using this form: "I baptize thee in the name
of Christ."

_On the contrary,_ Pope Pelagius II wrote to the Bishop Gaudentius:
"If any people living in your Worship's neighborhood, avow that they
have been baptized in the name of the Lord only, without any