Teshuva in its fullest form means that God will forgive without punishment if an individual or society repents, regretting its misdeeds and putting aside its evil ways.
It is clear that this concept developed over time and did not exist in the earliest stages of our religion. Let us compare, for example, the story of Jonah to that of the Flood. In the Flood story God informs Noah that He has seen the corruption of that generation and that therefore He is going to destroy the entire generation and save only Noah, his family and enough animals to reproduce. Noah is instructed to build an ark in order to save himself and the others. In due course the Flood comes and all are destroyed.
The story told in Jonah is very similar.
The people of Nineveh (non-Jews, incidentally - or not so incidentally) are very wicked. Their wickedness has come before God and He has decided to destroy them - unless - and this is the big difference - unless they repent. Jonah is sent on a mission to warn them of their imminent destruction. What is the purpose of telling them that? Obviously it is intended to bring them to repentance.
Unlike the generation of the Flood, if they repent, destruction will be avoided. Setting aside Jonah's personal problems in this regard for a moment, eventually he does convey the message and - lo and behold - led by their king, they listen, they repent. In the words of the king, "Let everyone turn back from his evil ways and from the injustice of which he is guilty" (Jonah 3:8). As a result no punishment comes upon them.
Why was Noah not sent on a similar mission? Some midrashim actually add that element to the Flood story, influenced by the Book of Jonah.
But the concept of teshuva was not yet known. This is evident from another destruction story - Sodom and Gomorrah. There too a prophet, Abraham, is told what will happen. He too does not venture forth to warn the people. He argues with God, but it is on the basis of negating collective punishment. He does not want the innocent to perish with the guilty and would prefer the guilty to live if there is a minimum core of decent people in those cities. This is truly a plea for justice or mercy, but here too there is no mention of calling upon the wicked to repent.
The closest we get to that idea in the Torah is in Leviticus 26:40-42 and Deuteronomy 30:8-11 when, after describing the punishment that will come upon the people if they forsake the covenant, they are told that after their punishment they will return to God and atone and He will forgive them.
It is in the prophetic books, however, that the doctrine of repentance is spelled out. In Jeremiah 4:1 God declares to Israel that "if you return to Me, if you remove your abominations from My presence" the forthcoming destruction will be avoided. Hosea in 14:2-5 similarly states that if they return to Him "I will heal their affliction, generously will I take them back in love." The idea is also found in Psalms. See, for example, Psalm 51.
This is the message that Jonah conveys and the lesson that the book teaches. Jonah personifies objection to that idea. He does not want to warn the people because he does not want the people of Nineveh to be spared the punishment he thinks is their due. After the fact he castigates God and says, "That is why I fled beforehand to Tarshish. For I know that You are a compassionate and gracious God... " (Jonah 4:2).
Through the incident of the gourd, which shrivels up and dies leaving Jonah exposed to the beating sun, God attempts to teach Jonah the value of forgiveness, of caring for others, but the book does not tell us if Jonah got the message or not.
Full repentance, as eventually defined by the medieval philosophers, requires a recognition and acknowledgment of sin, feelings of remorse, a desire for forgiveness and a resolution not to repeat what has been done.
A wonderful midrash sums it all up by asking the three sections of the Bible to describe the punishment of the sinner. Wisdom (the Writings) answers that misfortune will pursue him. Prophecy answers, quoting Ezekiel 18:4, that the sinner will die. The Torah answers that he can bring a guilt offering and be forgiven. But God Himself answers and says, "Let him repent and his sin will be atoned." (Y. Makkot 31:d).
The Book of Jonah, then, is more than an intriguing tale. It is the proclamation of the doctrine of repentance, a work that urges all to repent and that teaches us to be sensitive to others, even to those who sin - as we all do.
The writer is the head of the Rabbinical Court of the Masorti Movement and the Rabbinical Assembly of Israel.