Against The Valentinians by Tertullian
Chapter XXIX.--The Three Natures Again Adverted to They are All Exemplified Amongst Men. For Instance, by Cain, and Abel, and Seth.
I will now collect from different sources, by way of conclusion, what they affirm concerning the dispensation of the whole human race. Having at first stated their views as to man's threefold nature -- which was, however, united in one in the case of Adam -- they then proceed after him to divide it (into three) with their especial characteristics, finding opportunity for such distinction in the posterity of Adam himself, in which occurs a threefold division as to moral differences. Cain and Abel, and Seth, who were in a certain sense the sources of the human race, become the fountain-heads of just as many qualities of nature and essential character. The material nature, which had become reprobate for salvation, they assign to Cain; the animal nature, which was poised between divergent hopes, they find in Abel; the spiritual, preordained for certain salvation, they store up in Seth. In this way also they make a twofold distinction among souls, as to their property of good and evil -- according to the material condition derived from Cain, or the animal from Abel. Men's spiritual state they derive over and above the other conditions, from Seth adventitiously, not in the way of nature, but of grace, in such wise that Achamoth infuses it among superior beings like rain into good souls, that is, those who are enrolled in the animal class. Whereas the material class -- in other words, those which are bad souls -- they say, never receive the blessings of salvation; for that nature they have pronounced to be incapable of any change or reform in its natural condition. This grain, then, of spiritual seed is modest and very small when cast from her hand, but under her instruction increases and advances into full conviction, as we have already said; and the souls, on this very account, so much excelled all others, that the Demiurge, even then in his ignorance, held them in great esteem. For it was from their list that he had been accustomed to select men for kings and for priests; and these even now, if they have once attained to a full and complete knowledge of these foolish conceits of theirs, since they are already naturalized in the fraternal bond of the spiritual state, will obtain a sure salvation, nay, one which is on all accounts their due.