God works best through incarnation. When he wanted to tell men who he was, what he was, and how he wanted men to live, he spoke through prophets, priests, patriarchs, and kings, and the Old Testament writings came to us this way. However, men did not seem to understand the message, and for nearly four hundred years he ceased to speak. Then, "in the fullness of time," he came himself in the person of his own Son--born in the womb after the fashion of a human baby, passed through boyhood in the likeness of a boy and on into manhood as a man--to teach us who he was, what he was, and how he wanted us to live; and Jesus is just God spelling himself out in human history in the language that men understand. This is incarnation, and as he was compelled to pour himself out into man to reveal himself to men, so men and women who have seen him must literally pour themselves out--incarnate themselves--into the lives of growing boys and girls if these boys and girls of the teen age are to know him. Leadership has always been the cry of the world and the Church, and the history of both is written in biography. The Pharaoh, the Caesar, Charlemagne, Peter the Great, William the Silent, Henry of Navarre, Queen Elizabeth, Ferdinand and Isabella, Columbus, the Pilgrim Fathers, Washington, Lincoln, and the names of the great on the world's scroll of fame tell the world's story. The Christ, Peter, John, Paul, Augustine, Savonarola, Huss, Wycliffe, Luther, Zwingli, Knox, Roger, Williams, Wesley, Finney, Moody, Booth; and "what shall I more say? for the time would fail me to tell of 'those' of whom the world was not worthy," and whose splendid achievements fill out the glorious history of the Church--these, all of these, in their life and effort constitute the story of the Kingdom. The story is not yet complete. Still the world writes its progress in the names of its great ones. And yet, as always, the Church must look for its progress to its Christ-kissed men and women. While teen age boys and girls escape us at the rate of one hundred thousand a year, the need for leadership is among us. There is no boy problem. There is no girl problem. Boys and girls are the same yesterday, today and forever. The processes of their developing life are as the laws of the Medes and Persians, without change, eternal as the hills. Like the poor, they are always with us. There is neither boy nor girl problem; it is a problem of the man and a problem of the woman. Leadership is the key that unlocks the door of the teen age for the Church. The need of the Sunday school in the teen age today is leadership. The organized classes for men and women can solve the problem of the Church among the teen age boys and girls. The number of teachers an organized adult class produces is the measure of its ultimate usefulness in the Kingdom.