Chapter VIII.--The Gnostic So Addicted to Truth as Not to Need to Use an Oath.
The man of proved character in such piety is far from being apt to lie and to swear. For an oath is a decisive affirmation, with the taking of the divine name. For how can he, that is once faithful, show himself unfaithful, so as to require an oath; and so that his life may not be a sure and decisive oath? He lives, and walks, and shows the trustworthiness of his affirmation in an unwavering and sure life and speech. And if the wrong lies in the judgment of one who does and says [something], and not in the suffering of one who has been wronged,  he will neither lie nor commit perjury so as to wrong the Deity, knowing that it by nature is incapable of being harmed. Nor yet will he lie or commit any transgression, for the sake of the neighbour whom he has learned to love, though he be not on terms of intimacy. Much more, consequently, will he not lie or perjure himself on his own account, since he never with his will can be found doing wrong to himself.
But he does not even swear, preferring to make averment, in affirmation by "yea," and in denial by "nay." For it is an oath to swear, or to produce  anything from the mind in the way of confirmation in the shape of an oath. It suffices, then, with him, to add to an affirmation or denial the expression "I say truly," for confirmation to those who do not perceive the certainty of his answer. For he ought, I think, to maintain a life calculated to inspire confidence towards those without, so that an oath may not even be asked; and towards himself and those with whom he associates  good feeling, which is voluntary righteousness.
The Gnostic swears truly, but is not apt to swear, having rarely recourse to an oath, just as we have said. And his speaking truth on oath arises from his accord with the truth. This speaking truth on oath, then, is found to be the result of correctness in duties. Where, then, is the necessity for an oath to him who lives in accordance with the extreme of truth?  He, then, that does not even swear will be far from perjuring himself. And he who does not transgress in what is ratified by compacts, will never swear; since the ratification of the violation and of the fulfilment is by actions; as certainly lying and perjury in affirming and swearing are contrary to duty. But he who lives justly, transgressing in none of his duties, when the judgment of truth is scrutinized, swears truth by his acts. Accordingly, testimony by the tongue is in his case superfluous.
Therefore, persuaded always that God is everywhere, and fearing not to speak the truth, and knowing that it is unworthy of him to lie, he is satisfied with the divine consciousness and his own alone  And so he lies not, nor does aught contrary to his compacts. And so he swears not even when asked for his oath; nor does he ever deny, so as to speak falsehood, though he should die by tortures.