In the midst of Paul’s argument for the bodily resurrection of believers, he offers a proverb: “Do not be deceived: ‘Bad company ruins good morals.’” (1 Cor 15:33). At first it seems a bit out of place—why would Paul be concerned about who the Corinthians are hanging around? Isn’t his focus on what they believe? Paul’s point is that your associations can influence what you believe, and what you believe influences your behavior. That’s one of the reasons why God instructs his believers to practice separation. A failure to separate from false teachers can lead believers to be corrupted by that false teaching—even if they currently have their doctrine correct.
In a sermon on this passage, Alistair Begg gives his pastoral exhortation to believers who do not separate from false churches, urging them to apply this verse.
If you hang around with these people who say there is no resurrection of the dead, although you think there is, you’ll start to believe just as they do. And when you start to believe as they do, then you will start to behave as they behave. And he said “I want you to understand it, bad company corrupts good character.”
Incidentally and in passing there is a word here I believe that had never struck me in studying this passage before. But there is a word here for these solid Christians who determine that they are going to stay in liberal churches where the minister does not believe the Bible and does not teach the Bible. And they’re staying there, they say, because they’re going to turn it around. I admire their zeal. I call in question their strategy. Why? Because of this statement: “Bad company corrupts good character.” You cannot sit and listen to nonsense week after week after week without imbibing a significant amount of that nonsense. And over twenty years of observation, I have yet to see a group turn a church around but I have seen many within those groups lose their flame, lose their passion, lose their light, lose their edge. Cause they wouldn’t apply the proverb clearly. It is the responsibility of every straight-shooting Christian to sit consistently under the effective, useful, clarifying, relevant preaching of the Word of God (33:26-34:49 of If There Is No Resurrection).