Why is Jesus called the salt of the earth?

In Matthew 5:13, Jesus instructs His disciples that they are the salt of the earth, indicating their role as preservative agents against moral decay. As salt was used in ancient times to preserve food, so too are believers to uphold the truth of the gospel and to maintain righteousness in society. This role is crucial; without the influence of God's people, the world would succumb to corruption and despair. Their presence is essential for the earth to continue as a vessel for God's mercy and grace.