Matthew Poole and continuators on 1 Corinthians 8:12

12 But when ye sin so against the brethren , and would their weak conscience , ye sin against Christ .

Sin is properly against God, for it is a breach of the Divine Law; but the violations of that part of the Divine Law, which concerneth our duty to our Neighbour, are called sins against our Brethren, that is, sins against God, in matters which concern our duty towards our Brethren.

The giving the weak judgments of others, by your examples, an occasion of sin, by venturing upon actions which they think sinful, is that which is here called a beating, or a wounding their weak consciences, because it is indeed an hurting and defiling of them.

This the Apostle determineth to be a sinning against Christ, both against the Law of Christ, concerning loving one another, and against the love of Christ, who in dying for the weakest Believers, hath shewed the highest degree of love imaginable to them, whom they are very far from following, who will not abate▪ themselves a small matter of liberty, where the use of it this or that way may very probably be an occasion of sin, and ruine to their brethrens Souls.