11:4 For if he who comes preaches another Jesus whom we have not preached, or if you receive a different spirit which you have not received, or a different gospel which you have not accepted—you may well put up with it!
5 For I consider that I am not at all inferior to the most eminent apostles. 6 Even though I am untrained in speech, yet not in knowledge. But we have been thoroughly manifested among you in all things.
Paul's greatest concern for Corinth, for Galatia, (Galatians chapter 1) and for all the churches he planted was that others would come after him teaching and preaching a different Jesus. Did it happen? You better believe it did. It did not just happen in local churches either. It happened on a massive scale. 'Another Jesus' became the official teaching of Christianity for centuries. What do I mean? Well first we have to know what Jesus Paul was preaching. Once we get a clear picture of the authentic Jesus, the lies and counterfeits become easy to see. Paul preached Jesus as the Lamb of God who took away the sins of the whole world. Study Romans and you will clearly see this. Jesus died for us when we were still His enemies. The wages of sin is death but Jesus came to offer a gift. That gift is life eternal with Him. A gift is only a gift if it is free. When Adam and Eve ate the fruit from the forbidden tree Jesus came to them in the garden free of charge. He killed an animal free of charge. He used the skin to cover them free of charge. He made them a promise that there was a way back from this tragic choice. The way back was also free.
When Jesus came to earth as one of us He boldly declared "I Am the Way, the Truth, and the Life. No one comes to the Father but by Me." He offered this Way (Himself) to everyone free of charge. Not once was cost ever attached to anything Jesus did or offered. The Bible declares "Come and buy without money and without price."
However Christianity began to change. It was subtle at first. Jesus plus circumcision was one teaching. Jesus plus feast keeping was another teaching. Slowly and subtly over decades and centuries Jesus was less than enough. By the turn of the first millennium the church was developing a complex payment system for buying forgiveness. Jesus was painted and sculpted as still on the cross. Celebrating the Lord's supper turned into literally eating His flesh and drinking His blood, killing Him over and over. Why? Because once wasn't enough even the Bible boldly and clearly states that Jesus died once for all, rose from the dead and is seated in victory over sin and death beside His Father.
Teachings like confession to a human priest, penance, and indulgences became not only common place in Christianity but necessary. If you could afford to pay you had a chance to be forgiven. If you couldn't you were hopeless. This complex and demonic system of buying God's love and forgiveness took over Christianity almost completely until the dam broke in the 1500's and men like Martin Luther (himself a priest) stood up against the lies and declared what the Bible had been saying all along "The just will live by faith". As Jesus said over and over the only "requirement" is to believe that He has taken care of everything.
Sadly the war between the authentic Jesus and the elusive Jesus who demands payment of some kind continues in the hearts and lives of every person searching for peace with God. We still have churches and pastors even within my own church who present a Jesus + something else path to heaven. Don't listen to them. Go back to the Story. There is only One God, One Bible, and One story and His love, His grace, His mercy, His Son, His Spirit, everything is full and free to every single person on the planet. Good. News. Love Wins.