In the Sermon on the Mount, Jesus teaches his disciples about what it means to be a true follower of God. In Matthew 5:13, he compares his followers to salt, saying "You are the salt of the earth." By using this analogy, Jesus is saying that his followers should be a positive influence on the world around them. Salt was used as a seasoning and preservative in ancient times, and Jesus is saying that his followers should have a similar impact on the world.
He also emphasizes that if the salt loses its saltiness, it is no longer good for anything and would be trampled underfoot. This is an important message for his followers to understand that in order to be effective in spreading the message of God, they must maintain their purity and be consistent in their faith.
In this context, Jesus is encouraging his followers to be the light in the darkness, the salt in the blandness, and the hope in despair. He's reminding them that they are called to be agents of change in the world, to make a difference, to bring flavor and preservation to the world around them. They are to be the embodiment of the kingdom of God, bringing God's love, compassion, and justice to the world.
In essence, being the salt of the earth means to be a faithful and active disciple of Jesus Christ, living out his teachings and being a positive influence on those around us.