Even after John Gregory died in 1898, his Seven Laws of Teaching are still recognized and used. One, the Law of the Lesson, says the teacher must use what students already know to explain what they don’t know. Paul the Apostle never heard of John Gregory, but he understood that principle. So in speaking on Mars Hill, he used what the Athenians already knew to explain what they did not know. Here is what we read in Acts chapter 17: “So Paul, standing before the council, addressed them as follows: ‘Men of Athens, I notice that you are very religious in every way, for as I was walking along I saw your many shrines. And one of your altars had this inscription on it: “To an Unknown God.” This God, whom you worship without knowing is the one I’m telling you about. He is the God who made the world and everything in it. Since he is Lord of heaven and earth, he doesn’t live in man-made temples, and human hands can’t serve his needs—for he has no needs. He himself gives life and breath to everything, and he satisfies every need. … For in him we live and move and exist.’” So today, in order to explain unfamiliar Bible truths to others, we might do as Paul did—use what people already know to explain what they do not know.