e I. 9. 4; [Greek: houto de kai ho
ton kanona tes aletheias akline en heauto katechon hon dia tou
baptismatos eilephe], "in like manner he also who retains immovably in
his heart the rule of truth which he received through baptism"); because
it is this, it is apostolic, firm and immovable.[38]

By the fixing of the rule of truth, the formulation of which in the case
of Irenaeus (I. 10. 1, 2) naturally follows the arrangement of the
(Roman) baptismal confession, the most important Gnostic theses were at
once set aside and their antitheses established as apostolic. In his
apostolic rule of truth Irenaeus himself already gave prominence to the
following doctrines:[39] the unity of God, the identity of the supreme
God with the Creator; the identity of the supreme God with the God of
the Old Testament; the unity of Jesus Christ as the Son of the God who
created the world; the essential divinity of Christ; the incarnation of
the Son of God; the prediction of the entire history of Jesus through
the Holy Spirit in the Old Testament; the reality of that history; the
bodily reception ([Greek: ensarkos analepsis]) of Christ into heaven;
the visible return of Christ; the resurrection of all flesh ([Greek:
anastasis pases sarkos, pases anthropotetos]), the universal judgment.
These dogmas, the antitheses of the Gnostic regulae,[40] were
consequently, as apostolic and therefore also as Catholic, removed
beyond all discussion.

Tertullian followed Irenaeus in every particular. He also interpreted the
(Romish) baptismal confession, represented it, thus explained, as the
_regula fidei_,[41] and transferred to the latter the attributes of the
confession, viz., its apostolic origin (or origin from Christ), as well
as its fixedness and completeness.[42] Like Irenaeus, though still more
stringently, he also endeavoured to prove that the formula had descended
from Christ, that is, from the Apostles, and was incorrupt. He based his
demonstration on the alleged incontestable facts that it contained the
faith of those Churches founded by the Apostles, that in these
communities a corruption of doctrine was inconceivable, because in them,
as could be proved, the Apostles had always had successors, and that the
other Churches were in communion with them (see under C). In a more
definite way than Irenaeus, Tertullian conceives the rule of faith as a
rule for the faith,[43] as the law given to faith,[44] also as a "regula
doctrinae" or "doctrina re