The idea of this article is to determine the sense of the Logos in the Prologue of John's gospel by making use of the subsequent Christian doctrinal tradition. As an introduction, the general influence of Hellenistic Judaism on early Christian speculative theology and exegesis is illustrated by examples from Philo and Justin. Justin's exegesis is evaluated in accordance with the principle of Wilhelm Bousset, that learned scriptural demonstration (Schriftgelehrsamkeit) is not the source of doctrine but a post-rationalisation of existing doctrines. Then, Justin's argument from Scripture for Logos-Christology (Dial. 61—62), which is based on Genesis 1:26 and Wisdom 8:22—30, is taken as the point of departure. This argument informs us about the philosophical ideas behind Justin's Logos-Christology, which according to Bousset's principle preceded it. Further, it is argued that Justin's scriptural argument shows that the traditional derivation of the Logos of the Prologue from the word of creation of Genesis 1 did not exist at that early stage, since if it did, that derivation ought to have appeared in Justin. Since no other derivation of a Logos in the cosmological sense from the Bible is possible, the presence of this idea in John can only be explained as the result of influence from the eclectic philosophy of Jewish Hellenism (Philo). This conclusion is confirmed by the demonstration that the idea of universal innate knowledge, familiar from Justin's doctrine of the Logos, also appears in the Prologue of John. The argument for this is that it cannot be fortuitous that the traditional translation of John 1:9 lends itself to this interpretation. As the idea of universal innate knowledge is an idea unique to Greek philosophy, this observation settles the matter definitively. The origin of the traditional interpretation of the Logos goes back to Tertullian's interest in producing an exegesis that complies with the Latin translation of John 1.