Paul approaches his concluding words with a series of exhortations:
God has not left it up to us to define good and evil.
This principle puts us Christians into conflict with our own society, and sometimes at odds with other Christians. Libertarianism is taking over the United States, and one of the features of Libertarianism is that each person has the right to decide how they shall use their own body. Atheistic libertarianism also teaches that each person decides what is right or wrong for themselves.
In this passage, the Lord speaking through Paul lists various forms of evil. Evil = sexual immorality (any form of sex outside of heterosexual marriage), impurity (any sexual motive that falls short of Biblical standards), and sensuality (living for pleasure, which usually ends up involving sex). Paul does not waste time defending the idea that homosexuality is evil, since it is obviously unnatural and evil in its rebellion against God's creation.
Evil = idol-worship and the occult (which are often linked together).
Evil = enmities, strife, jealousy, outbursts of rage, disputes, dissensions, factions, and envy. All manifestations of hostility.
Evil = Drunkenness, carousing, and "things like these." Notice how Paul adds the catch-all phrase "things like these", to counter the person who tries to slip around God's standards by protesting that the Bible "never says nuthin' about 'blank'". The Bible doesn't need to always spell it out. This verse can be applied to all forms of mind-altering substances, even though the Bible never uses words like "heroin" or "LSD."
A person who willfully, stubbornly continues in these various wicked behaviors has no right to an assurance of his or her own salvation. Paul in 1st Corinthians 6:9-10 says that fornicators, idolaters adulterers, the effeminate, homosexuals, thieves, covetous, drunkards, revilers, and swindlers will not inherit the kingdom of God.
This doesn't mean that Christians can't fall before temptation in these areas, or never have on-going struggles with physical addiction (e.g., a heroin-user who comes to Christ will still suffer from the effects of heroin use). But Paul's list assumes a willful, voluntary character to these sins, and the context [church discipline] implies that these sins are knowingly persisted-in without repentance; otherwise the person wouldn't be put out of the church, 1 Cor. 5:13. That's a different scenario from a weak Christian who is striving by faith to break free from enslaving habits.
Side-note: Paul doesn't mention tobacco, since tobacco was only discovered in the Americas; but cannabis and various intoxicating compounds (often in the form of incense) did exist in the Middle East, from ancient times. Paul's use of the word "drunkenness" spoke to effect, and likely included inhaled intoxicants.
Tobacco use certainly is foolish, because of the harmful effect tobacco has on one's God-given body. But nicotine is different from, say, hashish or even strong wine because nicotine doesn't inflame violent impulses, distort the senses, or put a person into a trance state. We know that many immoral and violent acts happen because of drunkenness. Narcotics were and are used by occultists to commune with the so-called spirit world. It makes sense that, in light of the fact that the Lord forbids sexual immorality, violence, and occultism, He also forbade the use of substances that lead to those sins.
Paul does not offer assurance to salvation to anyone who is knowingly, willfully, and habitually living in sin.