Matthew 5:27-30 New Revised Standard Version (NRSV)
Concerning Adultery
27 “You have heard that it was said, ‘You shall not commit adultery.’ 28 But I say to you that everyone who looks at a woman with lust has already committed adultery with her in his heart. 29 If your right eye causes you to sin, tear it out and throw it away; it is better for you to lose one of your members than for your whole body to be thrown into hell.[a] 30 And if your right hand causes you to sin, cut it off and throw it away; it is better for you to lose one of your members than for your whole body to go into hell.[b]

Mark 8:34-38 New Revised Standard Version (NRSV)
34 He called the crowd with his disciples, and said to them, “If any want to become my followers, let them deny themselves and take up their cross and follow me. 35 For those who want to save their life will lose it, and those who lose their life for my sake, and for the sake of the gospel,[a] will save it. 36 For what will it profit them to gain the whole world and forfeit their life? 37 Indeed, what can they give in return for their life? 38 Those who are ashamed of me and of my words[b] in this adulterous and sinful generation, of them the Son of Man will also be ashamed when he comes in the glory of his Father with the holy angels.”