“And if your hand or your foot causes you to stumble, cut it off, and cast it from you. It is good for you to enter into life maimed or lame, rather than having two hands or two feet to be cast into the eternal fire. And if your eye causes you to stumble, pluck it out, and cast it from you. It is good for you to enter into life with one eye, rather than having two eyes to be cast into the Gehenna of fire.”
Attention is then turned to the one being caused to stumble, and this includes us all. For in the end we cannot blame others. Stumbling is in the end something that we do ourselves. And examples are then given of the great effort that must be put into avoiding any likelihood of stumbling. Again Jesus uses the method of exaggerated illustrations. If someone has stumbled, then rather than stumbling again through the temptations of hand, foot or eye it would be better for them to rid themselves of that hand, foot or eye that caused the stumbling, by cutting it off, or gouging it out, and hurling it away. The thought is of instantly ridding oneself violently of the causes of sin, without hesitation, because of the awareness of the awfulness of the sin. This is presented in an exaggerated picture of an instant response by hacking off the hand or foot and hurling it away, or of an instant gouging out of the eye and flinging it from them (compare Matthew 5:29-30), so that the sin will not happen again. In other words it is vividly describing a violent reaction. No violent reaction is to be thought of as too great in order to avoid sin. We should be ready to do anything in order to be rid of the cause of sin!
It is not, of course, intended to be taken literally. Removing hand, foot or eye will in fact make little difference to whether we sin in the future. (It may in fact result in more sin). It is what is in the heart that must be rooted out (Matthew 15:19-20). So the idea is rather that sin must be countered in the most severe way possible by the individual concerned. It was not intended to be a method of punishment, nor to be carried out in the cool light of day (such a sad and grotesque idea was left to a desert warrior prophet speaking to backward and fierce warrior tribes in Arabia who were used to chopping people up, and equally carried out by grotesque people who enjoy the same cruelty today). The point was rather the necessity of personally taking immediate and extreme action against sin as soon as it was committed, so as to avoid it happening again, and that because of its dreadful consequences. And the reason for the drastic action was that not to deal with such sins would be to be in danger of forfeiting eternal life and ending up in the eternal fire of Gehenna (the place of flaming destruction, the eternal Rubbish Dump where the maggots never die or cease consuming the rubbish, and the incinerating fire never goes out - Mark 9:48). It was a warning that we all ought to take more seriously.
Notice once again the choice of the two ways which is so emphasised in Matthew (Matthew 7:13-27; Matthew 6:14-15; Matthew 6:19-24; Matthew 6:32-33; Matthew 10:13-14; Matthew 10:28; Matthew 10:32-33). Better to enter into life maimed, than enter into eternal destruction as a whole person. (In future this would have a deeper significance when Christians were tortured and deliberately maimed, accepting it joyfully for the privilege of suffering for His name's sake).