Romans 10:14-21 (KJV)

14. 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?
15. And how shall they preach, except they be sent? as it is written, How beautiful are the feet of them that preach the gospel of peace, and bring glad tidings of good things!
16. But they have not all obeyed the gospel. For Esaias saith, Lord, who hath believed our report?
17. So then faith cometh by hearing, and hearing by the word of God.
18. But I say, Have they not heard? Yes verily, their sound went into all the earth, and their words unto the ends of the world.
19. But I say, Did not Israel know? First Moses saith, I will provoke you to jealousy by them that are no people, and by a foolish nation I will anger you.
20. But Esaias is very bold, and saith, I was found of them that sought me not; I was made manifest unto them that asked not after me.
21. But to Israel he saith, All day long I have stretched forth my hands unto a disobedient and gainsaying people.

Every Christian is a preacher. We have been sent by Christ to announce (preach) the good news. A preacher is not a moralizer or a motivator. A preacher is a memorizer of the gospel. We are called to broadcast the news that Christ takes away sins and gives a perfect righteousness to all who will call upon Him. However, not everyone who hears the good news believes. "But they have not all obeyed the gospel" (v.16). To obey the gospel is to believe. This is why it is called "obedience of faith" (1:5). The Jewish people (1). Heard the gospel (v.18), (2). Knew the gospel (v.19), (3). Rejected the gospel (v.21).

Why is it so difficult for a sinner to believe on Jesus Christ? Four major reasons:

1. The truthfulness of God's Word is doubted.
   Paul said that the good news has been broadcast "into all the earth" (v.18). Moses even prophesied to the Jewish people that God would deliver the Gentiles (v.19). But like people of our day, the Jews doubted the word of God. It is impossible to believe what God says about salvation if you can't believe what He says about history.
2. The preacher of the gospel is despised.
   As the Gentiles were coming to faith in the righteousness that God provides, the people of Israel were angered: "a foolish nation will anger you" (Romans 10:19). You and I are the gospel broadcasters. However, you and I are as sinful as the people in need of the gospel. Sometimes the hearers, not understanding the gospel, look at those who have faith in Christ and say, "I'm better off than him!" E.V. Hill says, "It's hard for those in a Cadillac to believe they need the message of those in a Pinto."
3. The message of salvation is different.
   We are all by nature performers. We live in a culture that adores achievers. From the crib we are rewarded when we do good; and we are punished when we do bad. The gospel is a message of grace. You can do nothing to obtain the righteousness required by God except believe in Christ. This is why it is called "the righteousness of God which is received by faith" (Philippians 3:9). What is required for a person to believe in Christ is to understand historical facts. This is why Christianity is not attempting to become a better person, but dying to self and trusting Christ Jesus.
4. The heart of the hearer is dead. God says, "All day long I have stretched forth my hands unto a disobedient and gainsaying people" (v.21). These two adjectives could be translated "disbelieving and argumentative people." The gospel is clear. The good news is factual. Christ died for the ungodly. You cannot obtain your right standing before God by your performance. However, this is absolute foolishness to the heart that is dead. God must regenerate the heart of the sinner before there is ever any love for Christ. "Winners of souls must first be weepers for souls" Charles Haddon Spurgeon.