καὶ τὴν μάχαιραν τοῦ πνεύματος, ὅ ἐστιν ῥῆμα θεοῦ—“and the sword of the Spirit, which is the word of God.” The last genitive is that of source, and the relative ὅ is neuter, by attraction or assimilation. This is the only offensive weapon which the Christian soldier is to assume. That sword is described as being the “word of God.” By “the word of God” we understand the gospel, or revealed will of God-and to us it is in effect Holy Scripture, not in any restricted sense, as limited either to its commands or its threatenings. Theodore of Mopsuestia says, however, that ῥῆμα θεοῦ is equivalent to θεοῦ ἐνέργεια-referring in proof to such phrases as “by the word of the Lord the heavens were made,” the meaning of which is easily understood. And this weapon—“the word of God”-is “the sword of the Spirit,” for it is the Spirit who supplies it. By the special organic influence of the Spirit, plenary inspiration was enjoyed, and God's ideas became, in the lips and from the pens of apostles and prophets, God's words. The genitive, πνεύματος, thus indicates the relation in which God's word stands to the Spirit. How strange on the part of Harless, Olshausen, Matthies, Stier, and von Gerlach, to make it the genitive of apposition, and to represent the sword as the Spirit Himself! In this erroneous view they had been preceded by Basil, who has adduced this verse as a proof that not only the Son, but the Spirit, is called the Word-the Son being the Word of the Father, and the Spirit the Word of the Son. Contra Eunom. lib. v. cap. 11. Such an exposition only darkens the passage, and compels Olshausen himself to ask in perplexity a question which his own false exegesis originates-How can the Word of God be represented as the Spirit? and he answers the insoluble query by a statement no less erro neous and unintelligible, that the Spirit is an operation which the Word of God produces. Harless argues, that as the previous genitives specifying the pieces of armour are those of apposition, so analogy must justify the same syntax in this clause. But the argument is wholly out of place, and that because the apostle subjoins an explanation. Had he simply said “the sword of the Word,” then according to the analogy of previous clauses the exegesis of Harless and Olshausen would be the correct one, but he enters into fuller and more precise detail. Away at the other extreme from this exposition is that of Chrysostom in one of his interpretations, of OEcumenius and Theophylact, with Michaelis and Grotius, which makes the clause merely mean—“take the spiritual sword of the Word; and still more remote is the lame exegesis of Morus, Rosenmüller, and de Wette, which understands by “spirit” the human spirit, as if the apostle meant to say—“take your soul's best sword, the word of God.”
The word of God is thus the sword of the Spirit, by which the spiritual foe is cloven down. The Captain of salvation set the example, and once and again, and a third time, did He repel the assault of the prince of darkness by three brief and simple citations from Scripture. Diplomacy and argument, truce and armistice, are of no avail-the keen bright sword of the Spirit must be unsheathed and lifted.
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http://www.studylight.org/commentaries/ ... k=eph&ch=6