Jonah 3:1–5, 10 “Then the word of the LORD came to Jonah the second time, saying,  “Arise, go to Nineveh, that great city, and call out against it the message that I tell you.”  So Jonah arose and went to Nineveh, according to the word of the LORD. Now Nineveh was an exceedingly great city, three days’ journey in breadth.  Jonah began to go into the city, going a day’s journey. And he called out, “Yet forty days, and Nineveh shall be overthrown!”  And the people of Nineveh believed God. They called for a fast and put on sackcloth, from the greatest of them to the least of them… When God saw what they did, how they turned from their evil way, God relented of the disaster that he had said he would do to them, and he did not do it.”
The first thing these few verses from the Old Testament prophet Jonah teaches us is trust.
God tells Jonah to go to Ninevah and deliver a message that he will give him. God does not give Jonah the message until he gets there. In other words, “Go, and trust me to give you the message.”
Jonah probably had a good idea what the message was to be. When God first called him to go there he told him, “Arise, go to Nineveh, that great city, and call out against it, for their evil has come up before me.” (Jonah 1:2)
This is what God did with Abraham and others in the Bible. He tells them to go and promises to fill in the details later.
God does the same with us. He tells us to go and promises to fill in the details. There is seldom a job description, just the command to go and to trust.
So Jonah went and did what the Lord asked and the people repented. Jonah gave them 40 days. Did they repent immediately or wait until day 39.5? Scripture gives the impression that they repented immediately but it wouldn’t surprise me if they waited. There are sure a lot of people today who keep putting off turning to the Lord. They think they have plenty of time to get their spiritual affairs in order.
The people of Ninevah repented. This is rare. The people of Israel, God’s chosen ones, hardly ever repented. As Stephen says in Acts 7:52 “Which of the prophets did your fathers not persecute? And they killed those who announced beforehand the coming of the Righteous One, whom you have now betrayed and murdered,”
The key to the people of Ninevah repenting was that they realized Jonah had been sent from God. Jonah was not just spouting off his own message of doom and gloom, they believed Jonah had truly been sent from God so they listened and repented.
The same is true today. Sometimes people think that when God sends someone to proclaim his word, especially if it is a call to change their ways, that they can ignore the message or attack the messenger. They do not realize the person is not speaking his own message but is speaking to them from God.
And when the people of Ninevah repented it says that God changed his mind. He decided not to destroy the city.
We should all be thankful that God does change his mind. When we repent God does not give us the punishment that our sins deserve. Instead, for the sake of Christ, we are forgiven.
It is like what parents do with their children. Parents tell their children to do something and tell them the consequences if they do not do it. If the children listen and do what the parents ask then the parents do not do what they have threatened. If the children do not do what the parents have asked then the parents will go through with what they have threatened.
And finally, do God’s prophets today still have the authority to speak out against secular authorities? Jonah was a prophet of God and Ninevah was an foreign city. What right did Jonah have to go and speak to them?
Do God’s prophets today have the same calling to speak out in the secular realm? Many believe that they do not. They believe that preachers and prophets should not speak at all in the secular realm.
This is one thing that seems to have changed from the Old Testament to the New Testament. In the Old Testament there are lots of examples of prophets denouncing the countries surrounding Israel.
In the New Testament prophets speaking to secular authorities is more by invitation only. The followers of Jesus are to speak to the secular authorities only if they are asked to do so. Jesus talks about this in Matthew 10:18–20 “You will be dragged before governors and kings for my sake, to bear witness before them and the Gentiles.  When they deliver you over, do not be anxious how you are to speak or what you are to say, for what you are to say will be given to you in that hour.  For it is not you who speak, but the Spirit of your Father speaking through you.”
So it appears the only time we are to speak out is when we are invited to do so.
Thankfully, God does not follow through when it comes to the threats of his law. If there was no way to get out from under the condemnations of the law we sinners would all be lost. Instead, when we repent God does not give us the punishment we deserve but forgives us for Jesus’ sake. Then he sends us out to go for him. We go, trusting that he will reveal to us his will as we go.