There is a notion that Praxeas, Tertullian’s enemy, was actually a pseudonym for St. Irenaeus. It is an interesting thought proposed by a very few, but it does begin to look remotely plausible when we begin to examine St. Irenaeus’s fight to keep Montanism from out of Rome.
Daniel Jennings has produced a remarkable collection of quotes and sayings found among the early Church writers concerning Montanism (HT). Here is St Irenaeus’ words, most different than what we would hear from Tertullian.
“Now one named Quintus, a Phrygian, who was but lately come from Phrygia, when he saw the wild beasts, became afraid. This was the man who forced himself and some others to come forward voluntarily . Him the proconsul, after many entreaties, persuaded to swear and to offer sacrifice. Wherefore, brethren, we do not commend those who give themselves up , seeing the Gospel does not teach so to do.” (Encyclical Letter Of The Church Of Smyrna On The Martyrdom Of Polycarp, Ch. 4)
“These things being so, all who destroy the form of the Gospel are vain, unlearned, and also audacious; those, who represent the aspects of the Gospel as being either more in number than as aforesaid, or, on the other hand, fewer. The former class , that they may seem to have discovered more than is of the truth; the latter, that they may set the dispensations of God aside. For Marcion, rejecting the entire Gospel, yea rather, cutting himself off from the Gospel, boasts that he has part in the the Gospel. Others, again (the Montanists), that they may set at nought the gift of the Spirit, which in the latter times has been, by the good pleasure of the Father, poured out upon the human race, do not admit that aspect presented by John’s Gospel, in which the Lord promised that He would send the Paraclete; but set aside at once both the Gospel and the prophetic Spirit. Wretched men indeed! who wish to be pseudo-prophets, forsooth, but who set aside the gift of prophecy from the Church; acting like those (the Encratitae) who, on account of such as come in hypocrisy, hold themselves aloof from the communion of the brethren. We must conclude, moreover, that these men (the Montanists) cannot admit the Apostle Paul either. For, in his Epistle to the Corinthians, he speaks expressly of prophetical gifts, and recognizes men and women prophesying in the Church. Sinning, therefore, in all these particulars, against the Spirit of God, they fall into the irremissible sin.” (Against Heresies, 3:11:9)
“He shall also judge false prophets, who, without having received the gift of prophecy from God, and not possessed of the fear of God, but either for the sake of vainglory, or with a view to some personal advantage, or acting in some other way under the influence of a wicked spirit, pretend to utter prophecies, while all the time they lie against God.” (Against Heresies, 4:33:6)