Satan loves nothing better than for people to think he doesn't exist.
Don't make that mistake!
If you are a follower of Jesus Christ, you're engaged in spiritual warfare. And you are the spoils of war that the devil wants to take and you are the great prize God wants to save for His kingdom.
The closer you are to Christ, the more the devil wants to take you and the more temptations to sin--whether the renunciation of faith, treating others lovelessly, adultery, despair, idolatry, bearing false witness, taking God's Name in vain, or others--he will push your way.
If you aren't a follower of Jesus, you will remain blissfully ignorant of the war going on for you. That, sadly, will indicate both that the devil is confident that he has you in his pocket and that you have either never heard of the new life Jesus gives to those who repent and believe in Him--shame on the Church and on Christians, if that's the case--or that you have never opened yourself to the saving help that God provides to all who trust in Jesus.
Because we are, by nature, "in bondage to sin and cannot free ourselves," as we Lutherans often say in our confessions (cf., Psalm 51:5 and Romans 5:12), we are incapable of resisting temptations to sin with our own strength of will or character.
We can't choose to believe in Christ. We can only choose to surrender and let God create both faith in Christ within us and the power to resist temptation and live as the free children of God we were meant to be.
We need to rely entirely on Christ.
In this connection, I find the second verse of Martin Luther's hymn, A Mighty Fortress is Our God, especially comforting and empowering:
"No strength of ours can match his [the devil's] might!
"We would be lost, rejected.
"But now a champion comes to fight [Jesus],
"Whom God Himself elected.
"You ask Who this may be?
"The Lord of hosts [God's angelic armies] is He!
"Christ Jesus, mighty Lord,
"God's only Son adored.
"He holds the field victorious!"
In 1 Corinthians 10:13, you can read: "No testing has overtaken you that is not common to everyone. God is faithful, and He will not let you be tested beyond your strength, but with the testing He will also provide the way out so that you may be able to endure it." I have learned the truth of this Biblical promise. Whenever I have truly wanted to resist temptation, I've been able to call on my "champion," Christ, and resist.*
Don't be fooled. Satan does exist. So does the temptation created by Satan, the world, and our sinful selves.
But Jesus Christ, crucified and risen, is alive today and stands ready to fight for and empower any who are humble enough to rely on Him to give them forgiveness, life, and the power to resist temptation and keep on trusting in Him.
Jesus is the champion who has come to fight for you. Let Him.
[For more on this subject, see here.]
*Conversely, there have been times when I have conveniently ignored God's will
in order to commit the sins I've wanted to commit. In such instances, I have
thought that I was exercising my free will, when in fact, I was making
the only kinds of choices we can make when we spurn the freedom from sin
and death God only provides for those who cling to Christ: bad ones.