Origen

“ And when these are defiled, they make all things whatsoever they touch defiled; as again on the contrary the pure mind and the pure conscience make all things pure, even though they may seem to be impure; for not from intemperance, nor from love of pleasure, nor with doubting which draws a man both ways, do the righteous use meats or drinks, mindful of the precept, “Whether ye eat or drink or whatsoever other thing ye do, do all to the glory of God.” ”

“ And any one who has carefully thought on these matters will see that, even in those things which are thought to be good, it is possible for a man to sin who has taken them up in an evil way and under the impulse of passion, and that these things called impure may be considered pure, if used by us in accordance with reason. ”

“ But as for us who know that some things are used by demons, or if we do not know, but suspect, and are in doubt about it, if we use such things, we have used them not to the glory of God, nor in the name of Christ; for not only does the suspicion that things have been sacrificed to idols condemn him who eats, but even the doubt concerning this; for “he that doubteth,” according to the Apostle, “is condemned if he eat, because he eateth not of faith; and whatsoever is not of faith is sin.” ”

“ We are clearly taught in these words by the Saviour that, when we read in Leviticus and Deuteronomy the precepts about meat clean and unclean, for the transgression of which we are accused by the material Jews and by the Ebionites who differ little from them, we are not to think that the scope of the Scripture is found in any superficial understanding of them. ”