“Don’t team up with those who are unbelievers. How can righteousness be a partner with wickedness? How can light live with darkness?” (2 Corinthians 6:14 NLT)

Paul’s warning does not mean separatism. He is not advising that we avoid unbelievers. In the previous chapter, Paul had just written about being entrusted with the “message of reconciliation,” so this requires engaging with lost people. What he is warning against is being partners with them. This should inform our plans for marriage, for church membership and other forms of partnership. Believers should not date or marry unbelievers. Churches should require belief before membership. Even business partnerships should be carefully considered. Successful partnerships have unity of vision and belief. When believers partner with unbelievers, this disunity of belief eventually leads to discord. Save yourself the pain and follow Paul’s advice.