John Calvin Commentary 1 Corinthians 8:7

"Howbeit there is not in all men that knowledge: but some, being used until now to the idol, eat as [of] a thing sacrificed to an idol; and their conscience being weak is defiled." — 1 Corinthians 8:7 (ASV)

But there is not in all that knowledge. He refutes, in a single word, all that he had previously set forth as their argument, showing that it is not enough that they know that what they do is right, if they do not at the same time have regard for their brothers and sisters.

When he said above—We know that we all have knowledge (1 Corinthians 8:1)—he referred to those whom he rebuked for abusing their liberty. Now, on the other hand, he calls them to consider that there are many weak and ignorant persons associated with them, for whom they should make allowances.

“You have, it is true, a correct judgment in the sight of God, and if you were alone in the world, it would be as lawful for you to eat of things offered to idols as of any other kinds of food. But consider your brothers and sisters, to whom you are debtors. You have knowledge; they are ignorant. Your actions should be regulated not merely according to your knowledge, but also according to their ignorance.”

This reply is particularly noteworthy, for there is nothing to which we are more prone than for everyone to follow their own advantage, neglecting that of others. Therefore, we are inclined to rely on our own judgment and do not consider that the appropriateness of the actions we perform in the sight of others depends not merely on our own conscience, but also on that of our brothers and sisters.

Some with conscience of the idol. This is their ignorance: they were still influenced by some superstitious notion, as if the idol possessed some power, or as if there were some power in a wicked and idolatrous consecration. Paul, however, does not speak of idolaters who were completely unfamiliar with true religion, but of ignorant persons who had not been sufficiently instructed to understand that an idol is nothing, and therefore that the consecration performed in the name of the idol is of no importance.

Their idea, therefore, was this: “As an idol is something, the consecration performed in its name is not altogether meaningless, and therefore those foods that have been once dedicated to idols are not pure.” Consequently, they thought that if they ate of them, they became polluted to some degree and were, in a way, participants with the idol. This is the kind of offense that Paul rebukes in the Corinthians—when we induce weak brothers and sisters, by our example, to do anything against their conscience.

And their conscience. God desires us to attempt nothing unless we know for certain it is pleasing to Him. Therefore, whatever is done with a doubting conscience is, as a result of such doubts, wrong in God's sight. And this is what He says (Romans 14:23): Whatsoever is not of faith is sin.

This confirms the truth of the common saying that “those build for hell who build against their conscience.” For just as the goodness of actions depends on the fear of God and integrity of conscience, so, on the other hand, there is no action, however good it appears, that is not polluted by a corrupt inclination of the mind.

For the person who does anything in opposition to conscience thereby reveals some contempt of God, for it is a sign that we fear God when we respect His will in all things. Therefore, you show contempt for God if you even move a finger while uncertain whether it might displease Him.

As to foods, there is another thing to be considered, for they are not sanctified for us otherwise than by the word (1 Timothy 4:5). If that word is lacking, nothing but pollution remains—not that God’s creatures are polluted in themselves, but because a person’s use of them is impure. In short, just as people’s hearts are purified by faith, so without faith there is nothing that is pure in the sight of God.