How do we know that preaching is central to Christianity?

In 1 Corinthians 1:21, Paul states that it pleased God through the foolishness of preaching to save those who believe. This underscores the importance of preaching as God's ordained means of communicating His message of salvation. Preaching should focus on the cross of Christ and convey the truth of Scripture rather than relying on human wisdom or eloquence. It is through this proclamation that believers are edified and brought to faith, showing that preaching holds a vital place in the life of the church and in the fulfillment of the Great Commission.