How do we know the preaching of the gospel is necessary?

Romans 10:14-15 makes clear the necessity of preaching for salvation: 'How then shall they call on Him in whom they have not believed? And how shall they believe in Him of whom they have not heard? And how shall they hear without a preacher?' God has chosen preaching as the vehicle for delivering the message of salvation. It is through this means that God sovereignly brings His people to Himself. The act of preaching reflects God's will and serves to glorify Him and honor His plan for redemption.