On the Making of Man by Gregory of Nyssa — Read

What then is that which includes the knowledge of good and evil blended together, and is decked with the pleasures of sense? I think I am not aiming wide of the mark in employing, as a starting-point for my speculation, the sense of "knowable. " It is not, I think, "science" which the Scripture here means by "knowledge"; but I find a certain distinction, according to Scriptural use, between "knowledge" and "discernment": for to "discern" skilfully the good from the evil, the Apostle says is a mark of a more perfect condition and of "exercised senses," for which reason also he bids us "prove all things," and says that "discernment" belongs to the spiritual man: but "knowledge" is not always to be understood of skill and acquaintance with anything, but of the disposition towards what is agreeable -- as "the Lord knoweth them that are His"; and He says to Moses, "I knew thee above all"; while of those condemned in their wickedness He Who knows all things says, "I never knew you."

The tree, then, from which comes this fruit of mixed knowledge, is among those things which are forbidden; and that fruit is combined of opposite qualities, which has the serpent to commend it, it may be for this reason, that the evil is not exposed in its nakedness, itself appearing in its own proper nature -- for wickedness would surely fail of its effect were it not decked with some fair colour to entice to the desire of it him whom it deceives -- but now the nature of evil is in a manner mixed, keeping destruction like some snare concealed in its depths, and displaying some phantom of good in the deceitfulness of its exterior. The beauty of the substance seems good to those who love money: yet "the love of money is a root of all evil": and who would plunge into the unsavoury mud of wantonness, were it not that he whom this bait hurries into passion thinks pleasure a thing fair and acceptable? so, too, the other sins keep their destruction hidden, and seem at first sight acceptable, and some deceit makes them earnestly sought after by unwary men instead of what is good.