1 Thess 5:21-22
But examine everything carefully; hold fast to that which is good; abstain from every form of evil. {NASB}
Keeping with your Paul epistles theme:
1 Corinthians 5:9-13 (NIV)
9 I wrote to you in my letter not to associate with sexually immoral people— 10 not at all meaning the people of this world who are immoral, or the greedy and swindlers, or idolaters. In that case you would have to leave this world. 11 But now I am writing to you that you must not associate with anyone who claims to be a brother or sister but is sexually immoral or greedy, an idolater or slanderer, a drunkard or swindler. Do not even eat with such people.
12 What business is it of mine to judge those outside the church? Are you not to judge those inside? 13 God will judge those outside. “Expel the wicked person from among you.”
1 Corinthians 6:15-20 (NIV)
15 Do you not know that your bodies are members of Christ himself? Shall I then take the members of Christ and unite them with a prostitute? Never! 16 Do you not know that he who unites himself with a prostitute is one with her in body? For it is said, “The two will become one flesh.” 17 But whoever is united with the Lord is one with him in spirit.
18 Flee from sexual immorality. All other sins a person commits are outside the body, but whoever sins sexually, sins against their own body. 19 Do you not know that your bodies are temples of the Holy Spirit, who is in you, whom you have received from God? You are not your own; 20 you were bought at a price. Therefore honor God with your bodies.
Hebrews 10:26-31 (NIV)
26 If we deliberately keep on sinning after we have received the knowledge of the truth, no sacrifice for sins is left, 27 but only a fearful expectation of judgment and of raging fire that will consume the enemies of God. 28 Anyone who rejected the law of Moses died without mercy on the testimony of two or three witnesses. 29 How much more severely do you think someone deserves to be punished who has trampled the Son of God underfoot, who has treated as an unholy thing the blood of the covenant that sanctified them, and who has insulted the Spirit of grace? 30 For we know him who said, “It is mine to avenge; I will repay,” and again, “The Lord will judge his people.” 31 It is a dreadful thing to fall into the hands of the living God