The Bible tells us how to live, but rather than doing so in lists of rules, it calls us to think about who we are as God’s people and how we should then live. Christians are a “new creation”. We are reconciled with God. How can one who is in fellowship with God then enter into compromising fellowship with unbelievers? Paul says that we should not, but then leaves it to us to reflect on the day-to-day applications of that principle.