1 Corinthians 6:
9. Know ye not that the unrighteous shall not inherit the kingdom of God? Be not deceived: neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor abusers of themselves with mankind,
10. Nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners, shall inherit the kingdom of God.
11. And such were some of you: but ye are washed, but ye are sanctified, but ye are justified in the name of the Lord Jesus, and by the Spirit of our God.
12. All things are lawful unto me, but all things are not expedient: all things are lawful for me, but I will not be brought under the power of any.
In other words, lost people live as they please, and although this side of Grace, all things are lawful, not all things are expedient; as a result, they were not to allow themselves to live as the lost do, for that is how the lost live - they have no boundaries.
Compare verse 11 with verse 20...
11. And such were some of you: but ye are washed, but ye are sanctified, but ye are justified in the name of the Lord Jesus, and by the Spirit of our God.
20. For ye are bought with a price: therefore glorify God in your body, and in your spirit, which are God's.
As he had had to remind the Galatians - "...ye have been called unto liberty; only use not liberty for an occasion to the flesh..." Gal. 5:13.