Matthew 18:9

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.

The subject upon which He here touches affects Jesus so deeply that He repeats His warning of the Sermon on the Mount, Matthew 5:29. Offenses will come, not only from without, but also from within, from one's own members. The hand, the foot, the eye present occasion for sinning. The law of sin is ever present in the organs of the body. To deny these members, to fight against every abuse of their God-given functions, to keep them in absolute control, that is the great concern of the disciple of Christ. That is not to be understood, as Luther says, that a person mutilate his body, but that he should keep his members in subjection with the help of the Holy Ghost, in true faith. The members must be cut off, that is, be subdued by the Spirit, in order that the hand, the eye, the feet do not perform what the sinful heart intends. For the end of him that yields to sin, that places his members into the willing service of sin, is everlasting fire, the fire of hell, where their worm will not die, neither will their fire be quenched, Mark 9:43. Only he who, through the power of the Holy Ghost within him, keeps his body in subjection, does not permit sin to gain the ascendancy, only he will retain faith and a good conscience, only he will save body and soul unto everlasting life.