Bantu were great worshippers, but they did not know the true God: the Savior of the World. Before bringing the Good News of Jesus Christ to Bantu people, Nassau wanted first to demonstrate the love of God by treating them as his brothers, sisters and treating himself as member of their society. What I just said in few words is a summary of who Dr. Nassau was and why he spent almost half a century among the Bantu in Africa. Nassau spent years and years learning Bantu people starting from his environment, his theology, his philosophy, his economy, his concept of the world and sociological forces that give him a place among human societies. The social approach of the gospel that Dr. Robert Nassau applied was not only fought against by other missionaries who reached African during those years of mission in Africa, but is unknown in the time natives took over creating autonomous churches. Until today, no one has learned from Nassau on where to start in order to reach Africans with the Good News of Salvation, method found by the true pioneer of the Presbyterian Mission in West Africa; he first considered the ethical and practical aspects of life in accordance with evangelical theology. Looking at the administrative and practical aspects of the vast majority of African churches in 2016, one who knows history of Christianity in Africa would not wonder if African Christian negative experience of the past would not be repeated. Throughout Africa and because of non practical life of Christian ethic, Islam has become the invader. When examining missionary efforts in Africa between the 18th and 19th centuries, it is no exaggeration to say that Christianity has not made Africans true believers. We should not attribute those failures to the missionaries, but to the autonomous and indigenous churches who are not fulfilling their mission. If modern world changed from pagan worshipers to true disciples of Jesus Chris, Nassau did not see why such a transformation would not happen in Africa if his principles were applied. If the biblical instruction that produces faith is properly taught and believed, if the commandments of God are obeyed, and the divine promises embraced, there is no doubt that African souls would be saved. This process was the basis of Dr. Nassau's missionary plan. Because the principles of evangelical philosophy established by Dr. Nassau were not put into practice by the missionaries of his time, African churches are now mixing paganism and Christianism, and have no way to avoid the religious syncretism, the same factor that had destroyed the work of the first Portuguese missionaries in Black Africa. Today, few African Churches know and live according to the line of demarcation line which should be between paganism and Christianity. Christian ethics in practical life is what is missing within African Christianity. For that reason, the principles of evangelical philosophy found by Dr. Nassau must be put into work by African autonomous Churches in order to help them to avoid repeating the history of Christianity in Black Africa.