If thy hand or thy foot offend thee. — (See Notes on Matthew 5:29-30.) The disciples had heard the words before in the Sermon on the Mount, but their verbal reproduction, sharpened as by a special personal application addressed not to the multitude but to the Twelve, gave them a new and solemn emphasis.
Related Commentaries of Matthew 18:8
Matthew 18:8-9
8 Wherefore if thy hand or thy foot offend thee, cut them off, and cast them from thee: it is better for thee to enter into life halt or maimed, rather than having two hands or two feet to be cast into everlasting fire.
9 And if thine eye offend thee, pluck it out, and cast it from thee: it is better for thee to enter into life with one eye, rather than having two eyes to be cast into hell fire.