The document outlines three time periods in which God interacts with humans, starting from the patriarchal age to the time of Moses leading the Israelites from Egypt. It emphasizes the call for individuals to return to God, culminating in the role of Christians as ambassadors of Christ, tasked with living in a way that draws others back to God. The text also prepares readers for a deeper exploration of personal evangelism and the significance of living a life that reflects Christ's teachings.