1. The Word of God in the Prophet's Mouth
Christians do not believe that the Qur'an is the Word of God but, purely for the sake of argument, we shall proceed as if God did indeed put his words in Muhammad's mouth to discover whether this might prove that Muhammad is the prophet referred to in Deuteronomy 18:18. In our view the statement “I will put my words in his mouth” does not help to identify the prophet referred to at all. It is true of every prophet that God has put his words in his mouth. For God said to Jeremiah:
Furthermore we also read in Deuteronomy 18:18 that the prophet to follow Moses “shall speak to them all that I command him”. Now we read that Jesus once said to his disciples:
A similar text which illustrates this point is found in the great prayer which Jesus prayed on the last night that he was with his disciples. He said:
In no way, therefore, can the identity of the prophet in the text of Deuteronomy 18:18 be established from the fact that God would put his words in his mouth. With every prophet who is true this is the case and the great prophet referred to in the text, who would be uniquely like Moses in a way that none of the other prophets were, must accordingly be identified from other sources.