In Acts 2:14-41 we read about Peter preaching to the Jews. The Jews already had an understanding of who the Lord God was based on their study and memorization of the Old Testament. They understood the foundations of their faith based on Genesis Chapters 1 through Genesis 11 that God created the heavens and the Earth, all forms of life, and that the first man, Adam, rebelled against God thus passing the sin nature onto his descendants. Because of their foundational knowledge, when Peter preached to the Jews about Jesus and his plan of salvation, they understood why they needed a savior, and many were saved that day.
This was not the case in Acts 17:22-34. Paul was preaching the Gospel to the Greeks. They were philosophers and pagans and had no understanding of God or the Christian faith. They did not know that they were born in sin nor even understand what sin was. When Paul preached to the Greeks, he did not start off by telling them that they are born in sin and in need of a savior. Instead, he started in Genesis and built the Christian doctrine from the ground up. This is the only way the pagan Greeks would understand what Paul meant. The Greeks were not fully receptive to Paul, although some said that they would like to hear more from him.
It is important that we understand the principles of the faith that is found in Genesis. Some may say that America is a Christian nation, and in the past this was true, but today, despite having the most Christian book stores, seminaries, and churches, we as a nation have distanced ourselves far away from Christianity. Today’s culture has been indoctrinated with the teaching of the Theory of Evolution, that there is no absolute truth, and morality is relative. Evolution Theory teaches that we are products of random processes and there is no need for a God in regards to the formation of life. Today, when talking about God and sin, we have to define our terms because not everyone has a Christian background. When presenting the Gospel, we must first show why the Gospel was needed, like Paul did, and that requires us to start from the very beginning: Genesis. This principle needs to be applied to all Christians who are in the mission field at home, work, and school, and to those who go overseas.