The People of Nineveh Repent

The people of Nineveh took Jonah’s message seriously and believed that he was speaking the truth. They realized that they had been living in a way that displeased God, so they decided to change their ways in the hope of receiving His mercy.
To show their repentance, they fasted, meaning they chose not to eat for a period of time as a sign of humility and sorrow for their wrongdoings. They also prayed to God, asking for forgiveness, and stopped engaging in their wicked actions. Even the king of Nineveh, the most powerful man in the city, humbled himself. He removed his royal robes, put on rough clothing made of sackcloth, and sat in ashes—an ancient symbol of deep remorse and humility before God.
The king urged his people to repent sincerely, saying, “Who can tell? Perhaps God will have mercy on us. Maybe He will change His mind and turn away from His fierce anger so that we will not be destroyed.” (Jonah 3:9)

Because God saw the genuine sorrow and change in the hearts of the people of Nineveh, He chose to spare the city from destruction. Instead of carrying out the punishment that had been warned, He showed them compassion and mercy.