The answer
You need to distract these thoughts and not to entertain them. Bad thoughts are sins and need to be confessed: "For out of the heart proceed evil thoughts, murders, adulteries, fornications, thefts, false witness, blasphemies" (Matthew 15:19).We deal with bad thoughts through the power of the word of God, i.e., the Holy Scripture, even as the Lord Jesus Christ demonstrated when Satan tried to tempt Him: "But He answered and said, 'It is written, 'Man shall not live by bread alone, but by every word that proceeds from the mouth of God.''" (Matthew 4:4).
Everything is forgivable, except for blasphemy against the Holy Spirit, which is refusing to repent: "Therefore I say to you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven men" (Matthew 12:31).
Answered by His Eminence Metropolitan Youssef (opens in a new tab)