The Haftorah of Mincha includes the entire book of Yonah, which teaches about the power of repentance. The classic biblical story of Teshuva is that of Sefer Yonah.
Some of the themes of this story are:
- Yonah attempts to flee from Hashem – but one cannot escape because G-d’s presence is everywhere.
- Ninveh takes responsibility for their actions, to the point of pulling apart their homes to return the stolen bricks.
- The Kikayon plant which causes Yonah great distress when it dies and stops providing shade demonstrates that G-d doesn’t want to destroy humanity, which even includes wicked people. G-d wants humankind to repent and live moral and upstanding lives.