(3) Howbeit [there is] not in every man that knowledge: for (4) some with (k) conscience of the idol unto this hour eat [it] as a thing offered unto an idol; and their conscience being weak is defiled.
(3) The reason why that does not follow, is this: because there are many men who do not know that which you know. Now the judgment of outward things depend not only upon your conscience, but upon the conscience of those that behold you, and therefore your actions must be applied not only to your knowledge, but also to the ignorance of your brethren. (4) An applying of the reason: there are many who cannot eat of things offered to idols, except with a wavering conscience, because they think them to be unclean. Therefore if by your example they wish to do that which inwardly they think displeases God, their conscience is defiled with this eating, and you have been the occasion of this mischief.
(k) By conscience of the idol, he means the secret judgment that they had within themselves, by which they thought all things unclean that were offered to idols, and therefore they could not use them with good conscience. For conscience has this power, that if it is good, it makes indifferent things good, and if it is evil, it makes them evil.