Philo Judaeus Quod Deterius Potiori Insidiari Soleat 12

[12] But after you have examined into it, and after you have inspected it carefully, casting your eyes over the whole of the business, then examine, besides, those who have already given their attention to the matter, and who have become practisers of it, whether now that they do this they are in a sound state, and not mad, as the lovers of pleasure think who calumniate them and cover them with ridicule. And do not form a positive judgment in your own mind either as to the appearance of the matter, or as to the soundness of condition enjoyed by those who practise these things, before you have reported the matter to and laid it before the father; for the opinions of those who have only lately begun to learn are unstable and without any firm foundation; but the sentiment of those who have made some advance are solid, and from their opinions they must of necessity derive firmness and steadiness.