It is a phrase which is often stated but one that is unlikely explained. You must "call on the name of the Lord" to be saved. But what does it mean? How do we call on the name of the Lord today?
This command was also unclear to many of the Jews in the first century. The apostle Peter was preaching the gospel to thousands on the day of Pentecost wherein he quoted from the prophet Joel, "And it shall come to pass That whoever calls on the name of the LORD Shall be saved" (Acts 2:21).
After he testified against their deeds and after he gave irrefutable proof that Jesus was the Christ, the people were pierced to the heart and asked a very important question, "Men and brethren, what shall we do?" (Acts 2:37). If they knew "how to call on the name of the Lord, they would not have asked, "what shall we do?"