Romans 10:14-17 meaning

In order to call for help from someone, you have to believe in that person's power: How then will they call on Him in whom they have not believed (v 14)? In order to believe in someone, you must hear about them: How will they believe in Him whom they have not heard (v 14)? 

In order to hear about them, you must have someone tell you: And how will they hear without a preacher (v 14)? 

In order for someone to tell you, they must be sent: How will they preach unless they are sent (v 15)? 

Those who are sent and preach the gospel are doing something very good and beautiful: Just as it is written, "How beautiful are the feet of those who bring good news of good things (v 15)!" 

The chronological order of this preaching process looks like this: 

1. a preacher is sent to the lost, 
2. the preacher preaches the gospel of Jesus, 
3. the lost hear the good news of Jesus, they believe the good news of Jesus and are saved from hell to heaven, 
4. and they call on their Lord to help them in their daily life of living by faith. 

This is a picture of how preaching the gospel should logically and ideally work out, but Paul proceeds to use it to display the unbelief of the Jews.

Throughout history the Jewish people have heard this message of pursuing righteousness through faith and not the law (Romans 9:30-33): However, they did not all heed the good news (v 16). 

Paul quotes the Old Testament prophet to demonstrate this rejection: For Isaiah says, "Lord, who has believed our report?" So faith comes from hearing, and hearing by the word of Christ (vv 16-17). 

The Jewish people have heard the word of Christ. Paul is reiterating what he said in verse 8-11, that God does not need to send more messengers down from heaven, including Christ, because the messengers and Christ have already come. The message is already here and has been delivered to the Jewish people.

But what if someone has never heard the preaching of the gospel? What if someone never heard the word of the prophets? What if it was just something they didn't understand? Paul will now address that possibility.