Matthew 5:29 If your right eye causes you to stumble, gouge it out and throw it away. It is better for you to lose one part of your body than for your whole body to be thrown into hell. 30 And if your right hand causes you to stumble, cut it off and throw it away. It is better for you to lose one part of your body than for your whole body to go into hell.
This will probably shock you: I believe that Jesus meant it literally when he said that. But wait, please. Do not call me a fundamentalist, or heartless, or a wooden literalist, before you hear the rest:
It is not the thief’s hands that make him stumble.
It is not the liar’s tongue that make him stumble.
It is not the fornicator’s eyes, which saw someone he now lusts after, that make him stumble. Nor is it his genitals, her dress or her body.
Jesus identifies, a few sentences earlier in the same teaching, where the sin comes from:
Matthew 15:19 For out of the heart come evil thoughts—murder, adultery, sexual immorality, theft, false testimony, slander.
God offers a new heart to those who follow Jesus – a renewal of their way of thinking and living. That old heart, the wrongful attitudes and character attributes we now have, should be gouged out/ cut off.
Just before the “gouge it out” part in Matthew 5:29-30, Jesus say:
Matthew 5:28 But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart.
If a man looks with the goal of lusting, there is sin in his heart. The sin is not in her hips or breasts, her God-given body does not make him sin. Nor is the sin in his God-given eyes or genitalia. The sin is in the attitude of his heart.
So, cutting out the part that sins means cutting out the (figurative, not literal blood-pumping) old heart, and let Jesus give you a new one.