Jesus told his disciples:

27 “You have heard that it was said, ‘You shall not commit adultery;’ 28 but I tell you that everyone who gazes at a woman to lust after her has committed adultery with her already in his heart. 29 If your right eye causes you to stumble, pluck it out and throw it away from you. For it is more profitable for you that one of your members should perish, than for your whole body to be cast into Gehenna. 30 If your right hand causes you to stumble, cut it off, and throw it away from you. For it is more profitable for you that one of your members should perish, than for your whole body to be cast into Gehenna."

Matthew 5:27-32 - World English Bible

After his commentary on murder, Jesus turned his attention to adultery (Exodus 20:4), stressing not the act, but the desire. Above all, lust preceded adultery, so he addressed the urge with the metaphor of self-mutilation (ironically, an act that violated the Law; see Leviticus 19:28). When he said "pluck out and cast away" one's eye, he meant turn away from the cause of lust; when he said "cut off" your right hand, he meant end the relationship of a best friend (the person on one's right") if he led you into lust. Self control and a wise choice of friends were far better than a life marred by lust and eternal condemnation.

How have you chosen your friends? Do they help or hinder your self-control?