1 Corinthians 15:19

If in this life only we have hope in Christ, we are of all men most miserable (KJV)

Then: To think that their belief in Christ only applies to their days on earth means that they are persecuted by Jews and by Caesar without purpose (Henry). Why not abandon it and avoid the pain? This is the third problem or effect in lives of Corinthians who follow Christ.

Now: The promise of believing in Christ sometimes accompanies a perception, that the days of misery on earth, problems of all kinds are gone. This is to misunderstand the work of the Holy Spirit, the life of Christ, and call to follow him. What Jesus promises is to stand with us and make a way through the difficulties. He uses all things for good, purifies us from the evil within us and calls us to show love to others before the day of judgment comes.

Extra Source: Commentary on the Whole Bible Acts to Revelation Vol VI by Matthew Henry online at http://www.ccel.org/ccel/henry/mhc6.iCor.xvi.html