After we come to know God personally through submitting our allegiance to Jesus Christ, Satan and demons strive to deceive us into thinking that what is actually fun (loving Jesus by obeying his commandments) is scary and/or boring, and that what is scary or boring is “fun.” Since believers in Jesus are dead to sin and given a new nature, although it is possible for us to choose sin by believing the devils’ lies (like how Adam in the Garden could sin even without possessing a sin nature yet), we can no longer sin and enjoy it. See Romans 6.
Jesus says, “If you love me, you will keep my commandments.” That includes: “You have heard that it was said, ‘You shall not commit adultery.’ But I say to you that everyone who looks at a woman with lustful intent has already committed adultery with her in his heart. If your right eye causes you to sin, tear it out and throw it away. For it is better that you lose one of your members than that your whole body be thrown into hell. And if your right hand causes you to sin, cut it off and throw it away. For it is better that you lose one of your members than that your whole body go into hell.” (Matthew 5:27-30 ESV) See the blogpost “When to Judge Sexual Sin” for further investigation.
Once we get filled with the Spirit of the fear of the Lord in our new hearts, then sexual immorality will feel repulsive, boring, and scary. We’ll [super]naturally think, “Why would I ever want to do such a disgraceful, unloving thing like that?” c.f. Isaiah 11:2; Genesis 39:9b; 1 John 3:3-10. Jesus came that we'd have life and have it abundantly. He also demonstrated what this exciting life is like when he went around doing good, healing all who were oppressed by the devil, introducing people to His Father, and celebrating their new birthday with a party when they receive this salvation. See John 10:10; Acts 10:38; Luke 15 & 19.
He commanded his followers to heal the sick, raise the dead, cast out demons, cleanse lepers, and preach the good news (reconciling people back to God). Satan hates it when we do that, because he's not fond of getting his butt kicked. Therefore he does all he can to persuade believers in Jesus that it's impossible or scary to obey Jesus’ commands, so we should throw in the towel on obeying everything Jesus commanded. However, casting out demons, introducing people to the ultimate Partier, healing the sick, etc. is actually fun (once we push past that initial fear and spiritual opposition through Christ who strengthens us). Satan is a thief and liar who wants to take that away from us, stealing our joy, excitement, and destiny.
Satan's tactics haven't changed. In the Garden of Eden, God gave Adam a commandant: Don't eat from the tree of the knowledge of good and evil. Satan came in and said, “Let's look at the context of what God said. Did He really mean what you interpret He said? What God's word really meant was something else. Therefore, things will go better for you if you eat of the tree of the knowledge of good and evil.”
He lies the same way today. He persuades believers, “When Jesus commanded his disciples to cast out demons, heal the sick, preach the gospel, raise the dead, etc., does Jesus expect you to obey that today? That was for the apostles and early church, but the times have changed. Trying to obey that is futile and will do more harm than good. It will embarrass you and Jesus. When Jesus said those things in John 14:12, Mark 16:17, Matthew 10:24f, etc., you can't trust those expired promises anymore.”
Or Satan will say, “Sex is a basic human need. Your body was designed to lustfully desire after others; otherwise no one would marry and humans would become extinct. It’s impossible to live without ‘even a hint of sexual immorality.’ You can’t live a holy life like Jesus did; it’s impossible. Your struggling with this sin is to keep you humble, so you shouldn’t raise your standard to perfection in holiness and purity. Then you’ll be arrogant when Jesus delivers you from your sinful habits.”
Make sure you are daily transformed by the renewing of your mind, hiding God’s word in your heart so that you will not sin against Him. c.f. Matthew 5:48; Ephesians 5:3ff; 1 John 2:1-6; Romans 12:2; Psalm 119:9-11.
Adam didn't listen to the voice of Truth, but to the voice of the liar. He thereby empowered the liar, giving his authority over to him. Now that all authority in heaven and on earth has been given to Jesus, we must learn to submit to his authority and use that authority to bring heaven down to earth and to destroy hell, “[f]or in him the whole fullness of deity dwells bodily, and you have been filled in him, who is the head of all rule and authority.” Colossians 2:9-10 ESV
To learn more about how Satan is the ultimate party-pooper and/or how you can enter a relationship with God, after which heaven will throw a party, see my post "Satan Wants to Take Away Your Fun."