16. But since the first part of this argument seems to be unfolded, we ought to touch on its subsequent part, on account of the heretics; because it is very necessary not to pass over that discussion which once falls into our hands, lest perchance some heretic should dare, of his subtlety, to assail those of our brethren who are more simple. For because John said that we must be baptized in the Holy Ghost and in fire, from the fact that he went on to say and fire, some desperate men have dared to such an extent to carry their depravity, and therefore very crafty men seek how they can thus corrupt and violate, and even neutralize the baptism of holiness. Who derive the origin of their notion from Simon Magus, practising it with manifold perversity through various errors; to whom Simon Peter, in the Acts of the Apostles, said, “Thy money perish with thee, because thou hast thought that the grace of God could be possessed by money; thou hast neither part nor lot in this work; for thy heart is not right with God.” And such men as these do all these things in the desire to deceive those who are more simple or more inquisitive. And some of them try to argue that they only administer a sound and perfect, not as we, a mutilated and curtailed baptism, which they are in such wise said to designate, that immediately they have descended into the water, fire at once appears upon the water. Which if it can be effected by any trick, as several tricks of this kind are affirmed to be—of Anaxilaus—whether it is anything natural, by means of which this may happen, or whether they think that they behold this, or whether the work and magical poison of some malignant being can force fire from the water; still they declare such a deceit and artifice to be a perfect baptism, which if faithful men have been forced to receive, there will assuredly be no doubt but that they have lost that which they had. Just as, if a soldier after taking an oath should desert his camp, and in the very different camp of the enemy should wish to take an oath of a far other kind, it is plain that in this way he is discharged from his old oath.