The Christological doctrine, drawn principally from the prologue of John's Gospel (John 1:1-18), that the eternal Son is the Logos (Word) of God. The Greek logos means word, reason, account, or rational principle; John takes the term (which had rich background in both Hebrew thought — the creative Word of God, the dabar YHWH — and Greek philosophy — the logos as the rational principle of the cosmos) and applies it to the eternal Son. The Johannine prologue establishes the foundational Logos Christology: (1) the eternal pre-existence of the Word — In the beginning was the Word (John 1:1a; the Word already existed in the beginning, before creation); (2) the distinct personhood of the Word in relation to God — and the Word was with God (John 1:1b; the Word in eternal relation with God-the-Father, distinct from Him); (3) the full deity of the Word — and the Word was God (John 1:1c; the Word is fully God, of the same divine essence); (4) the Word as the agent of creation — All things were made by him; and without him was not any thing made that was made (John 1:3; the Word as the divine agent through whom all things were created; cf. Colossians 1:16; Hebrews 1:2); (5) the incarnation of the Word — And the Word was made flesh, and dwelt among us (John 1:14; the eternal Word took human nature, the incarnation). The Logos Christology grounds the eternal deity, pre-existence, distinct personhood, creative agency, and incarnation of the Son. The patriarchal-Reformed reader holds the substantive Logos Christology of John's prologue against the various denials: the Arian denial (which would make the Logos a created being); the modalist denial (which would deny the Word's distinct personhood); and the liberal reduction (which would treat the Logos as a mere abstraction or principle rather than the eternal personal Son). The Logos who was in the beginning, who was with God, who was God, by whom all things were made, was made flesh and dwelt among us — this is the foundational Christology of John's prologue and the Reformed-confessional doctrine of the eternal Son who became incarnate for our salvation.