What is the biblical basis for the centrality of preaching in worship? Among many Protestants, preaching is often seen as the most important part of the worship service:


  Proclamation, the preaching of the gospel, should be central to Christian worship. The sermon is the central dynamic in the worship experience. (Annual Preacher's Sourcebook) 


Sermons thus are emphasized, but even beyond that, this often influences architecture.  The pastor's pulpit is brought to the center of the church, diminishing the focus on other aspects like the communion table. 

What is the biblical basis for understanding preaching to be the most important part of the worship service? Note the word most: of course the proclamation of the gospel is important, but why is it seen to be more important than things like singing, praying, and the Lord's supper? 



Question inspired by John Frame's Systematic Theology, chapter 27, p 645ff. and review question 11: Do you believe that preaching is "central" to Christian worship?
The prophet, as spokesperson for God, is the biblical basis for the centrality of preaching in worship. From the very beginning, and over and over since, God’s people are exhorted to listen.

Moses, probably through Aaron 1, said that God’s people should listen to God’s prophets. 


  The Lord your God will raise up for you a prophet like me from among
  you, from your fellow Israelites. You must listen to him. (Deuteronomy
  18:15)


Moses reminds God’s people that they asked for these spokespersons so they would not have to ever again fear and tremble at the direct word from God’s mouth.


  For this is what you asked of the Lord your God at Horeb on the day of
  the assembly when you said, “Let us not hear the voice of the Lord our
  God nor see this great fire anymore, or we will die.” (Deuteronomy
  18:16)


To which God commissions the prophet to proclaim God’s divine will.


  The Lord said to me: “What they say is good. I will raise up for them
  a prophet like you from among their fellow Israelites, and I will put
  my words in his mouth. He will tell them everything I command him.
  (Deuteronomy 18:17-18)


And over the next several hundred years, God’s prophets continued to make declarations of  God’s divine will.


  “Go and tell this people.” (Isaiah 6:9)
  
  “Speak my words to them, whether they listen or fail to
  listen.“(Ezekiel 2:7)
  
  “Go, prophesy to my people Israel.“ (Amos 7:15).


Jeremiah, toward a semblance of a ‘worship service’, makes a famous preaching engagement at the temple:


  Stand at the gate of the Lord’s house and there proclaim this message:
  “Hear the word of the Lord, all you people of Judah who come through
  these gates to worship the Lord.” (Jeremiah 7:2)


Hear. Listen. Shema. 2

Into which comes the forerunner, the baptist John, recognized as prophet before he was born. 


  “And he will go on before the Lord, in the spirit and power of
  Elijah.” (Luke 1:17)


The common people identified Jesus among John and the prophets.


  They replied, “Some say John the Baptist; others say Elijah; and still
  others, Jeremiah or one of the prophets.” (Matthew 16:14)


Jesus Christ identified himself with the prophets.


  A prophet is not without honor except in his own town and in his own
  home. (Matthew 13:57)


At Jesus’ transfiguration, again God’s intimidating direct word from the cloud, words that echo Jesus’ baptism.


  This is my Son, whom I love; with him I am well pleased. Listen to
  him! (Matthew 17:5)


The early church took Christ to be God’s promised prophet of Deuteronomy 18 who would proclaim God's word in the same fashion as did Moses. But still, God’s people need other humans to help them listen and hear.


  And how can they hear without someone preaching to them? (Romans
  10:14)


And finally, in what probably speaks most to the nebulous protestant preacher of the question, we have Paul’s slow burn of a command to Timothy:


  In the presence of God and of Christ Jesus, who will judge the living
  and the dead, and in view of his appearing and his kingdom, I give you
  this charge: Preach the word. (2 Timothy 4:1-2)


In conclusion, prophet is preacher throughout scripture entire and is the basis for the centrality of preaching to anything at all resembling the worship of God.



1 From the moment of Moses’ original commission, Moses objected to God that he could not speak because he was “slow of speech and slow of tongue.” God provided Aaron, one of the first appointed to speak God’s word. 

2 Shema Yisrael (or Sh'ma Yisrael; Hebrew: שְׁמַע יִשְׂרָאֵל‎; "Hear, [O] Israel") are the first two words of a section of the Torah, and is the title (sometimes shortened to simply Shema) of a prayer that serves as a centerpiece of the morning and evening Jewish prayer services