Adam Clarke's Commentary on the Bible

Verse 9 (1 Corinthians 8:9)

But take heed - Lest by frequenting such feasts and eating things offered to idols, under the conviction that an idol is nothing, and that you may eat those things innocently, this liberty of yours should become a means of grievously offending a weak brother who has not your knowledge, or inducing one who respects you for your superior knowledge to partake of these things with the conscience, the persuasion and belief, that an idol is something, and to conclude, that as you partake of such things, so he may also, and with safety. He is not possessed of your superior information on this point, and he eats to the idol what you take as a common meal.

- Adam Clarke's Commentary on the Bible