Apparently the Corinthians were ready to make wholesale changes without thinking through the ramifications. Paul was writing to say that people should be Christians where they are. You can do God’s work and demonstrate your faith anywhere. If you became a Christian after marriage, and your spouse is not a believer, remember that you don’t have to be married to a Christian to live for Christ. Don’t assume that you are in the wrong place, or stuck with the wrong person. You may be just where God wants you.
Each of you should continue to live in whatever situation the Lord has placed you, and remain as you were when God first called you. This is my rule for all the churches. (1 Corinthians 7:17 NLT)