At Corinth the apostle Paul had very successful and rewarding work. As his usual custom was, he began in the synagogue and each Sabbath reasoned and persuaded both Jews and Greeks. In keeping with God’s special instructions he remained working in that city for a year and a half. The narrative in Acts summarizes the Corinthians reception of the word: “And many of the Corinthians hearing believed, and were baptized.” (Acts 18:8) This corresponds to Jesus’ departing instruction to His disciples: “Go into all the world and preach the gospel to every creature. He that believeth and is baptized shall be saved; he that believeth not shall be damned.” (Mark 16:15-16)
Please note that there is no mention of a Sinner’s Prayer – not by Jesus and not by the apostle Paul. The Sinner’s Prayer model for salvation is not found anywhere in the Bible. It is not from God but an invention of man.