The Qu'ranic statement that 'Allah has no son' constitutes one of the essential differences between Islam and Christianity. Is Christian worship of God any different if one believes in the divine Son, or not? Is the doctrine of the Trinity an unnecessary belief? Frieling proposes that many Christians, faced with the straightforward monotheism of Islam, might ask themselves such questions. He starts by examining the roots of the divergence of the two spiritual streams carried by Abraham's sons, Ishmael and Isaac. He goes on to describe Muhammad's establishment of Islam with the Qu'ran as its fundamental revelation. The heart of the book revolves around Frieling's analysis of what is meant by 'the Son'. He argues that the divine Son has an essential role not only in humankind's relationship with God, but also in our entire evolution on earth. He also argues that the unfulfilled needs of a religion which overlooked 'the Son' were critical in the emergence of the Shiah branches of Islam. In this, he feels, can be detected an unconscious seeking for Christ.
Rudolf Frieling was born in 1901 in Leipzig, Germany. He studied theology and philosophy and was among those who founded The Christian Community in 1922. From 1960 until his death in 1986 he was its leader. His other works include Christianity and Reincarnation; Hidden Treasures in the Psalms; Old Testament Studies and New Testament Studies.