Jesus increased the purity requirement in Matthew 5, because now we have the Holy Spirit to help us overcome. He’s saying how serious lusting is, because it really will cost us our souls if we don’t overcome this.

27 “You have heard that it was said to those of old [old covenant], ‘You shall not commit adultery.’ 28 But I say [new covenant] to you that whoever looks at a woman to lust for her has already committed adultery with her in his heart. 29 If your right eye causes you to sin, pluck it out and cast it from you; for it is more profitable for you that one of your members perish, than for your whole body to be cast into hell. 30 And if your right hand causes you to sin, cut it off and cast it from you; for it is more profitable for you that one of your members perish, than for your whole body to be cast into hell.

Jesus gave me a WARNING DREAM about this very passage when I was in seminary in 1993, which led me to do this study, where I also talk about the dream: