This is strong talk. If we did not know Paul better we might wonder if this is from the same writer who had just poured out encouragement and the promise of prayer: eager for the effective witness and protection of the church in Thessalonica (2 Thessalonians 3:1-5). But it is from Paul, and it is designed to encourage their walk with the Lord. In 1 Corinthians 15:33, Paul said that bad company corrupts good character, and the instruction in today's verse demonstrates the importance of choosing godly companions.

This instruction comes with the highest authority – the Lord Jesus Christ Himself. It is not a suggestion, but a command addressed to the family of God. Doubtless it would have been read to all the believers, including those who had rejected the apostle's teaching and authority. Paul did not want to divide the fellowship, but rather to encourage a unity based on the teaching he brought from Jesus.

But if some believers persisted in a lifestyle condemned by apostolic teaching or were idle or disruptive, then the church had the responsibility to exclude them from fellowship. The principle is the same as in 1 Corinthians 5:1-5 in which an immoral believer was to be put out of the church. The aim was that the shame of isolation would bring repentance (2 Corinthians 7:8-13) and enable him to be restored (2 Corinthians 2:5-11). But failure to act appropriately would lead many others astray (Hebrews 12:15).

Today, in some parts of the world, the church is reluctant to exercise discipline. It may seem a reasonable option to smile at those who deny the apostle's teaching, even though Jesus sees such toleration as apostasy (Revelation 2:20). Of course, we must never hate the people. We must love them all for Christ's sake and long for them to be restored to fellowship with Christ (James 5:20). But if we accept, tolerate or ignore false teaching, our love of the truth is in doubt; as is our love for believers who have been captivated by error. Some might like to ignore this verse, but its divine authority is impossible to erase. So, pray for your spiritual leaders and support them as they seek to obey this verse. And, at the same time, do not get caught in the trap of encouraging what God's Word repudiates.