The Apostle Paul
1 Corinthians 8:7ESV·traditional attribution

However, not all possess this knowledge. But some, through former association with idols, eat food as really offered to an idol, and their conscience, being weak, is defiled.

John Calvin Reformed @genevareformer

7. But there is not in all that knowledge. He refutes, in a single word, all that he had previously brought forward in their name, showing that it is not enough that they know that what, they do is right, if they have not at the same time a regard to their brethren.

Matthew Henry Presbyterian @wholebiblehenry

The apostle, having granted, and indeed confirmed, the opinion of some among the Corinthians, that idols were nothing, proceeds now to show them that their inference from this assumption was not just, namely, that therefore they might go into the idol-temple, and eat of the sacrifices, and feast there with their heathen neighbours.

Commenting on 1 Corinthians 8:7-13

John Gill Reformed Baptist @doctorgill

Howbeit, there is not in every man that knowledge,.... The apostle is not speaking of Heathens, in whom there was no knowledge of the one true God, the author of all things, and of the one Lord Jesus, the only saviour and Redeemer; but of Christians, in whom there was the knowledge of these things, but not in all of them; the knowledge of this...