New life in Christ brought new freedom to believers in Corinth. However, like children or immature adults, they did not know how to behave responsibly to each other or to God. They needed to be taught, which was why Paul wrote this letter. The Spirit of God had given special abilities to different people, but instead of treating God's gifts as tools (for serving the Lord and spreading the gospel) they used them as toys to feed their pride.
 
Corinthian citizens and slaves were used to the idea of supernatural power: the mythical gods of the city were supposed to be able to command cosmic and earthly events. Many of the new believers in Jesus had previously grown up to think that the temple idols had personalities and authority (which was why they were worshipped and sacrifices were made to them). They now had to understand that the Holy Spirit has genuine power, but radically different from their indoctrinated ideas or demonic lies about idols.
 
So how could they recognise the difference between the pagan preachers, demonic miracle-workers, and Christians filled with the Holy Spirit? Paul's test was simple; what did they say about Jesus? If anyone cursed Jesus or failed to recognise Him as the Lord God of eternity, then the Holy Spirit was not speaking through them. But whoever announced that Jesus is the Lord to be worshipped and obeyed, demonstrated that the Holy Spirit lived in them. It was a dangerous claim to make about Jesus, and one for which the apostles faced severe persecution (Acts 4:13,17-18), so no one would fake the claim that 'Jesus is Lord' unless the Holy Spirit empowered them.
 
Being willing to announce the identity of Jesus is the critical evidence that the Holy Spirit is resident in a human heart. Jesus is more than just a good man, a wise teacher and a prophet. When people confess that 'Jesus is my Lord', you know they are saved and have the Holy Spirit (Romans 10:9-10). Their public identification with Him is also the beginning of their gospel witness. Others will be drawn to Jesus, even though believers may face difficulties from unbelievers. "What do you think of Jesus Christ?" is still a potent diagnostic evangelistic question in the community or workplace. Those who are ashamed of Jesus need to beware because He will be ashamed of them on the Final Day (Luke 9:26). So do not be ashamed to testify about our Lord (2 Timothy 1:8).