1. offense is an offense in which faith and love are abused. The faith is violated when someone teaches something different from what is written in the holy scriptures, because the faith of the neighbor is thereby subverted. Of this offense the Lord Christ says here in the Gospel: "If any man offend the least of these that believe on me, it were better for him that a millstone were hanged about his neck, and that he were drowned in the deepest part of the sea.
2. Love is abused when you do not help your neighbor and do not serve him in what is necessary or otherwise useful. Item, he who breaks the peace and incites other people to evil. This is what Christ says in Matthew 17:27, when he commanded Petro to give the toll. St. Paul also speaks of this trouble to the Romans Cap. 14, 13 and 1 Cor. 10, 32. If you want to know more about it, see the Annotationes and locos communes Philippi Melanchthonis.