Today’s story from Acts is the first sermon given exclusively to pagans. The method of evangelization has changed. When the apostles spoke to Jews or a mixed group, they would begin by detailing “salvation history;” use their Scriptures to lead to Jesus. But, this time, Paul and Barnabas appeal to reason and nature, something gentiles would understand. We teach that a person can discover that there is a God through reason and nature, but that Revelation is needed to understand the fullness of revelation and truth. So, we Catholics talk about Sacred Scripture and Sacred Tradition. Both point to the fullness of revelation, i.e. Jesus Christ.