Worship is communion with God. It is covenatal fellowship by which we enter into the blessings of eternal life. In worship the truth is manfested that God is our God and Father, that Jesus Christ is our Savior and Lord and that the Holy Spirit is in the midst of us as the body of Christ.
At the heart of that worship are two elements the preaching of the Word and prayer. Singing in public worship is a form of prayer. Whether it be of praise and thanksgiving, confessing our sins and need of Christ, or coming to God in our warfare with sin and afflictions prayer belongs to the center of Christian worship. Yet more central however is the role of the preaching of the Word.
Preaching of the Word is the true heart of worship. It is the command and commission of Christ himself, Matthew 28:19,20 and Mark 16:15. In preaching God speaks to us anmd we hear His Word. In preaching Christ is present with us by His Word and Spirit dso that we hear his voice, and know him as our saviour and shepherd and are called to faith and salvation John 10:3,4; John 10:16; Romans 10:11-15,17. Not man's word but God's Word is first and central.
The sacraments of baptism and the Lord's supper stand subordinated to the Word preached. They are signs and seals of the gospel and a visible representation of it. With out the preaching the sacraments would have no true meaning.
Preaching has always been at the heart of Christian worship Just as it was in Jesus' own ministry. He came as the chief prophet of the church to preach. In like manner the prophets of the Old Testament and the apostles in the New Testament had the preaching of the Word of God as their central calling.
Where preaching is omitted or where is is reduced to very little, true worship is destroyed. Worship is God centered. Such worship has at its heart hearing not speaking.
For further study: God to : Preaching the Heart of Worship
For a fuller discussion of preaching, catechism and the use of confessions in preaching see the following: