Theology of the Word can be defined as the totality of a specific theologian's understanding of God's Word and theological statements. This paper attempts to study Zwingli's theology of the Word and Barth's theology of the Word in turn, which has a Reformed theological continuity. At this time, Zwingli's key research topics on the theology of the Word were the sovereignty of the triune God, the Bible and preaching that make effect and give faith through the work and illumination of the Holy Spirit, the Light of God's Word(Jesus Christ) and the Light(inner illumination) that makes you realize the Word. Following Barth's key research topics on the theology of the Word were the three forms of God's Word(Jesus Christ-the Bible-Preaching), the Holy Spirit that makes the trifold Words recognizable, and the event of God’s Word. Preaching that is regarded as the proclaimed God’s Word requires consistent theological statements in its theory and practices. This paper proposes the theology of the Word(Zwingly and Barth's theology of the Word), which is the totality of understanding of God's Word and theological statements, as a theological basis and theological statements that can fundamentally discuss the theory and practices of preaching. The Homiletic Significance(The theological statements on the theory and practices of preaching), which is proposed based on the study of Zwingly and Barth's theology of the Word, is as follows. First, the subject of the preaching is the Triune God. Second, the contents of preaching that become the God’s word should be Jesus Christ, the Bible, and the Gospel. Third, preaching is the moment when the Light of Christ shines and the Holy Spirit is active, that is, the event of the Word.