Paul Earnhart on Matthew 5:27-30:
This passage is the place where those who staunchly affirm their confidence in the literal interpretation of all Scripture will have to take a very deep breath. There can be no question that Jesus builds His message on a truth from the world of the flesh, but it is evident from the context that His language has application to the world of the spirit (if the right eye was removed, the sinner could still lust just as effectively with his left). In these grim words the true depth of change which the Son of God is demanding finds dramatic expression. In the same vein Jesus spoke of our coming to Him as a crucifixion (Matthew 16:24-25) and Paul provides a commentary on Matthew 5:29-30 in his words to the Colossians: “Therefore put to death your members which are on the earth: fornication, uncleanness, passion, evil desire…” (Colossians 3:5).
Though our Lord is not speaking here of physical mutilation, which would be wholly ineffectual against the motions of the heart, we should not presume that the figurative intent of His words makes them any less intensely painful. There are “parts” of us—affections, habits, attitudes, values, relationships—which have become by long cultivation so intimately a part of our personality that their removal will make the actual excision of an eye or hand seem conservative. Most of us have spent a long time learning how to be selfish and lustful. We should not expect the end of these things to come without trauma. Shrieks of anguish may arise from somewhere within us as in penitence we apply the gospel knife. But some pain is good pain. “For he who has suffered in the flesh has ceased from sin” (1 Peter 4:1). We can choose to avoid this suffering but our cherished lusts will destroy us like some awful gangrene of the soul.