1 Corinthians 8:9
“For take heed,” says he, “lest by any means this liberty of yours become a stumbling-block to the weak among the brethren.” (τῶν ἀδελφῶν not in rec. text.)
He did not say, “Your liberty has become a stumbling-block,” nor did he positively affirm it that he might not make them more shameless; but how? “Take heed;” frightening them, and making them ashamed, and leading them to disavow any such conduct. And he said not, “This your knowledge,” which would have sounded more like praise; nor “this your perfectness;” but, “your liberty;” a thing which seemed to savor more of rashness and obstinacy and arrogance. Neither said he, “To the brethren,” but, “To those of the brethren who are weak;” enhancing his accusation from their not even sparing the weak, and those too their brethren. For let it be so that you correct them not, nor arouse them: yet why trip them up, and make them to stumble, when you ought to stretch out the hand? But for that you have no mind: well then, at least avoid casting them down. Since if one were wicked, he required punishment; if weak, healing: but now he is not only weak, but also a brother.
Source: Homilies on First Corinthians (New Advent)