The parable of the unforgiving servant highlights the concept of mercy and forgiveness, emphasizing the importance of extending forgiveness to others as we have received it ourselves. Jesus uses parables to convey this message, targeting those who struggle with being merciful and forgiving, such as the Pharisees. Through various parables like the publican and the Pharisee, and the prodigal son, Jesus contrasts self-righteousness with the humility of seeking mercy. The parables serve as a reminder of the deep mercy we have received from Jesus and the expectation for us to extend that mercy and forgiveness to others.