I have not written to you because you don't know the truth, but because you know it, and because no lie is of the truth.
and that no lie is of the truth; either springs from it, or is according to it, but just the reverse. The apostle has respect to the errors and heresies of the above apostates, which were flagrant contradictions to the Gospel, and as distant from it as a lie is to truth; and of such lies, and of those liars, he speaks in the next verses. The Arabic version reads, "and that every liar is not of the truth".