In 1689, an obscure French Reformed pastor undertook the task of publishing a detailed examination of a plurality in the Godhead in Jewish thought. He did this as a response to the growing crisis of Unitarianism that was beginning to rear its ugly head within Protestant Christianity. At the end of that book, a short dissertation appears to help convince a friend that the figure known as the Angel of the LORD in the OT was in fact the preincarnate Son of God. Republished here for the first time in over 200 years is that dissertation with excerpts from his larger volume and a myriad of quotations from Christian history on the Christological identity of the Angel in Genesis 48:16. What is contained herein is of considerable importance for helping people understand that Christ is not merely prophesied in the OT; he is literally present in it. May it be a corrective to a kind of functional Unitarianism that so many have when they read the pages of the OT.