In a debate with the atheist (and now deceased) Christopher Hitchens, William Lane Craig noted how Christ's arrival on earth occurred at the perfect time. Craig said:

Human beings have existed for thousands of years on this planet before Christ's coming. But what's really crucial here is not the time involved; rather, it's the population of the world. The Population Reference Bureau estimates that the number of people who have ever lived on this planet is about 105 billion people. Only two percent of them were born prior to the advent of Christ. Erik Kreps of the Survey Research Center of the University of Michigan's Institute for Social Research says, "God's timing couldn't have been more perfect. Christ showed up just before the exponential explosion in the world's population."

The Bible says in the fullness of time God sent forth his Son, and when Christ came, the nation of Israel had been prepared. The Roman peace dominated the Mediterranean world; it was an age of literacy and learning. The stage was set for the advent of God's Son into the world. And I think in God's providential plan for human history, we see the wisdom of God in orchestrating the development of human life and then in bringing Christ into the world in the fullness of time.