Now the word of the Lord came to Jonah the son of Amittai, saying, “Arise, go to Nineveh, that great city, and call out against it, for their evil has come up before me.”  (Jonah 1:1–2)

Up to this point in Jonah’s life, the silence from heaven regarding the pagan world might have suggested God was indifferent to it. But now, that silence was unexpectedly broken. Jonah, the parochial prophet, suddenly heard God telling him to leave his sheltered and comfortable life to cross the borders and preach God’s judgment to a people steeped in wickedness. 

Wake up!

"The word of the Lord came to Jonah" (Jonah 1:1). But how did he react to the command to go to Nineveh? Here he was, serving a local God, probably preoccupied with temple rituals—sacrifices and offerings, special days, and priestly garments. Maybe he thought that God wasn’t concerned about anything else. So long as the temple laws were followed to the letter, God would be happy. 

I can imagine God calling,

"Jonah!" 
"Yes, Lord?" 
"I want you to go to Nineveh." 
"Why, Lord?" 
"Because its wickedness has come up before me." 
"Of course they’re wicked—they’re heathen!" 

What a staggering thought for Jonah—that God should care about heathen Nineveh, let alone want to say anything to them. 

A light to the nations

In times of spiritual awareness, the Israelites knew they were called to be a light to the nations. Abraham had been told, "All peoples on earth will be blessed through you" (Gen. 12:3). And David, inspired by the Spirit, wrote, "Ask of me, and I will make the nations your inheritance, the ends of the earth your possession" (Psalms 2:8). He knew God’s purpose extended far beyond Israel to the nations of the world. 

When Israel was spiritually low, the people forgot the breadth of God’s government and became introspective. So long as they kept their own house in order, all would be well. God would bless them. The heathen were "out there somewhere," excluded from the promises and of no importance whatsoever. 

God has plans for the heathens

One Old Testament king glorified God, saying, “His dominion is an eternal dominion; his kingdom endures from generation to generation. All the peoples of the earth are regarded as nothing. He does as he pleases with the powers of heaven and the peoples of the earth. No one can hold back his hand or say to him, ‘What have you done?’” (Dan. 4:34–35). Clearly, this man knew that God ruled the nations. But who made this tremendous statement about God? Nebuchadnezzar—a pagan king. 

What a staggering thought for Jonah—that God should care about heathen Nineveh, let alone want to say anything to them. 

God also "anointed" Cyrus, and said of him, "He is my shepherd and will accomplish all that I please … [He will] subdue nations before him … I will give [him] the treasures of darkness, riches stored in secret places …" (Isa. 44:28; 45:1,3). Hearing these words, the average Jew likely protested, "Cyrus is a heathen king; he doesn’t know God. He can’t be included in God’s plans." But God had other ideas. 

Jesus is a light to all

He had these "other ideas" for the Messiah too! His prophetic word to his Son was, "It is too small a thing for you to be my servant to restore the tribes of Jacob … I will also make you a light for the Gentiles, that you may bring my salvation to the ends of the earth" (Isaiah 49:6). God knew that the Jewish nation was backslidden and desperately needed restoration, but ‘Operation Israel’ was too small a project for Jesus! God wanted his Son to reach not a little corner of the world, but all of it. 

The principle message of the book of Jonah is, "God’s interest and mercy extend far beyond the Jews to the whole human race. The readiness of the people of Nineveh to repent was also a salutary lesson to the Jews who were renowned for their stubbornness and lack of faith." –The New Bible Dictionary