The following is an excerpt from The MacArthur New Testament Commentary on John 1.

In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God. (1:1–2)The concept of the Word (logos) is one imbued with meaning for both Jews and Greeks. To the Greek philosophers, the logos was the impersonal, abstract principle of reason and order in the universe. It was in some sense a creative force, and also the source of wisdom. The average Greek may not have fully understood all the nuances of meaning with which the philosophers invested the term logos. Yet even to laymen the term would have signified one of the most important principles in the universe.

To the Greeks, then, John presented Jesus as the personification and embodiment of the logos. Unlike the Greek concept, however, Jesus was not an impersonal source, force, principle, or emanation. In Him, the true logos who was God became a man—a concept foreign to Greek thought.

But logos was not just a Greek concept. The word of the Lord was also a significant Old Testament theme, well-known to the Jews. The word of the Lord was the expression of divine power and wisdom. By His word God introduced the Abrahamic covenant (Gen. 15:1), gave Israel the Ten Commandments (Ex. 24:3–4; Deut. 5:5; cf. Ex. 34:28; Deut. 9:10), attended the building of Solomon’s temple (1 Kings 6:11–13), revealed God to Samuel (1 Sam. 3:21), pronounced judgment on the house of Eli (1 Kings 2:27), counseled Elijah (1 Kings 19:9ff.), directed Israel through God’s spokesmen (cf. 1 Sam. 15:10ff.; 2 Sam. 7:4ff.; 24:11ff.; 1 Kings 16:1–4; 17:2–4., 8ff.; 18:1; 21:17–19; 2 Chron. 11:2–4), was the agent of creation (Ps. 33:6), and revealed Scripture to the prophets (Jer. 1:2; Ezek. 1:3; Dan. 9:2; Hos. 1:1; Joel 1:1; Jonah 1:1; Mic. 1:1; Zeph. 1:1; Hag. 1:1; Zech. 1:1; Mal. 1:1).

John presented Jesus to his Jewish readers as the incarnation of divine power and revelation. He initiated the new covenant (Luke 22:20; Heb. 9:15; 12:24), instructs believers (John 10:27), unites them into a spiritual temple (1 Cor. 3:16–17; 2 Cor. 6:16; Eph. 2:21), revealed God to man (John 1:18; 14:7–9), judges those who reject Him (John 3:18; 5:22), directs the church through those whom He has raised up to lead it (Eph. 4:11–12; 1 Tim. 5:17; Titus 1:5; 1 Peter 5:1–3), was the agent of creation (John 1:3; Col. 1:16; Heb. 1:2), and inspired the Scripture penned by the New Testament writers (John 14:26) through the Holy Spirit whom He sent (John 15:26). As the incarnate Word, Jesus Christ is God’s final word to mankind: “God, after He spoke long ago to the fathers in the prophets in many portions and in many ways, in these last days has spoken to us in His Son” (Heb. 1:1–2).

Then John took his argument a step further. In His eternal preexistence the Word was with God. The English translation does not bring out the full richness of the Greek expression (pros ton theon). That phrase means far more than merely that the Word existed with God; it “[gives] the picture of two personal beings facing one another and engaging in intelligent discourse” (W. Robert Cook, The Theology of John [Chicago: Moody, 1979], 49). From all eternity Jesus, as the second person of the trinity, was “with the Father [pros ton patera]” (1 John 1:2) in deep, intimate fellowship. Perhaps pros ton theon could best be rendered “face-to-face.” The Word is a person, not an attribute of God or an emanation from Him. And He is of the same essence as the Father.

Yet in an act of infinite condescension, Jesus left the glory of heaven and the privilege of face-to-face communion with His Father (cf. John 17:5). He willingly “emptied Himself, taking the form of a bond-servant, and being made in the likeness of men.… He humbled Himself by becoming obedient to the point of death, even death on a cross” (Phil. 2:7–8). Charles Wesley captured some of the wonder of that marvelous truth in the familiar hymn “And Can It Be That I Should Gain?”:  He left His Father’s throne above,
  So free, so infinite His grace!
  Emptied Himself of all but love,
  And bled for Adam’s helpless race.
  Amazing love! How can it be
  That Thou, my God, shouldst die for me?
  Amazing love! How can it be
  That Thou, my God, shouldst die for me?John’s description of the Word reached its pinnacle in the third clause of this opening verse. Not only did the Word exist from all eternity, and have face-to-face fellowship with God the Father, but also the Word was God. That simple statement, only four words in both English and Greek (theos en ho logos), is perhaps the clearest and most direct declaration of the deity of the Lord Jesus Christ to be found anywhere in Scripture.

But despite their clarity, heretical groups almost from the moment John penned these words have twisted their meaning to support their false doctrines concerning the nature of the Lord Jesus Christ. Noting that theos (God) is anarthrous (not preceded by the definite article), some argue that it is an indefinite noun and mistranslate the phrase, “the Word was divine” (i.e., merely possessing some of the qualities of God) or, even more appalling, “the Word was a god.”

The absence of the article before theos, however, does not make it indefinite. Logos (Word) has the definite article to show that it is the subject of the sentence (since it is in the same case as theos). Thus the rendering “God was the Word” is invalid, because “the Word,” not “God,” is the subject. It would also be theologically incorrect, because it would equate the Father (“God” whom the Word was with in the preceding clause) with the Word, thus denying that the two are separate persons. The predicate nominative (God) describes the nature of the Word, showing that He is of the same essence as the Father (cf. H. E. Dana and Julius R. Mantey, A Manual Grammar of the Greek New Testament [Toronto: MacMillan, 1957], 139–40; A. T. Robertson, The Minister and His Greek New Testament [Reprint: Grand Rapids: Baker, 1978], 67–68).

According to the rules of Greek grammar, when the predicate nominative (God in this clause) precedes the verb, it cannot be considered indefinite (and thus translated “a god” instead of God) merely because it does not have the article. That the term God is definite and refers to the true God is obvious for several reasons. First, theos appears without the definite article four other times in the immediate context (vv. 6, 12, 13, 18; cf. 3:2, 21; 9:16; Matt. 5:9). Not even the Jehovah’s Witnesses’ distorted translation of the Bible renders the anarthrous theos “a god” in those verses. Second, if John’s meaning was that the Word was divine, or a god, there were ways he could have phrased it to make that unmistakably clear. For example, if he meant to say that the Word was merely in some sense divine, he could have used the adjective theios (cf. 2 Peter 1:4). It must be remembered that, as Robert L. Reymond notes, “No standard Greek lexicon offers ‘divine’ as one of the meanings of theos, nor does the noun become an adjective when it ‘sheds’ its article” (Jesus, Divine Messiah [Phillipsburg, N.J.: Presb. & Ref., 1990], 303). Or if he had wanted to say that the Word was a god, he could have written ho logos en theos. If John had written ho theos en ho logos, the two nouns (theos and logos) would be interchangeable, and God and the Word would be identical. That would have meant that the Father was the Word, which, as noted above, would deny the Trinity. But as Leon Morris asks rhetorically, “How else [other than theos en ho logos] in Greek would one say, ‘the Word was God’?” (The Gospel According to John, The New International Commentary on the New Testament [Grand Rapids: Eerdmans, 1979], 77 n. 15).

Under the inspiration of the Holy Spirit, John chose the precise wording that accurately conveys the true nature of the Word, Jesus Christ. “By theos without the article, John neither indicates, on the one hand, identity of Person with the Father; nor yet, on the other, any lower nature than that of God Himself” (H. A. W. Meyer, Critical and Exegetical Hand-Book to the Gospel of John [Reprint; Winona Lake, Ind.: Alpha, 1979], 48).

Underscoring their significance, John restated the profound truths of verse 1 in verse 2. He emphasized again the eternity of the Word; He already was in existence in the beginning when everything else was created. As it did in verse 1, the imperfect tense of the verb eimi (was) describes the Word’s continuous existence before the beginning. And as John also noted in verse 1, that existence was one of intimate fellowship with God the Father.

The truth of Jesus Christ’s deity and full equality with the Father is a nonnegotiable element of the Christian faith. In 2 John 10 John warned, “If anyone comes to you and does not bring this teaching [the biblical teaching concerning Christ; cf. vv. 7, 9], do not receive him into your house, and do not give him a greeting.” Believers are not to aid heretical false teachers in any way, including giving those who have blasphemed Christ food and lodging, since the one who does so “participates in [their] evil deeds” (v. 11). Such seemingly uncharitable behavior is perfectly justified toward false teachers who deny the deity of our Lord and the gospel, since they are under God’s curse: There are some who are disturbing you and want to distort the gospel of Christ. But even if we, or an angel from heaven, should preach to you a gospel contrary to what we have preached to you, he is to be accursed! As we have said before, so I say again now, if any man is preaching to you a gospel contrary to what you received, he is to be accursed! (Gal. 1:7–9)Emphasizing their deadly danger, both Paul (Acts 20:29) and Jesus (Matt. 7:15) described false teachers as wolves in disguise. They are not to be welcomed into the sheepfold, but guarded against and avoided.

Confusion about the deity of Christ is inexcusable, because the biblical teaching regarding it is clear and unmistakable. Jesus Christ is the eternally preexistent Word, who enjoys full face-to-face communion and divine life with the Father, and is Himself God.