What does the Bible say about the mystery of the gospel?

In Ephesians 3:1-7, Paul discusses the mystery of the gospel, highlighting how God reveals His truth to His chosen people. This mystery signifies that the salvation through Christ was not limited to the Jews but extended to the Gentiles as well. The scripture illustrates that the gospel is a revelation of God's grace, wherein both Jews and Gentiles are united as fellow heirs and partakers of God's promises. This mystery emphasizes that salvation comes solely by God's grace and is not based on human achievement or lineage but upon divine election and revelation.