Salt is a preservative that keeps meat from spoiling, and Christians with the attitudes of Jesus are like salt to the world. When disciples with Christ-like attitudes are "rubbed into" the people of the world as salt is rubbed into meat, their influence will keep the world from total corruption. They become a valuable commodity Jesus uses to revolutionize the culture. The second metaphor indicates that Christians are the only source of light for multitudes living in darkness. As with the first metaphor, Jesus' words literally mean that "you and you alone" are salt and light. If His disciples do not fulfill their role as salt and light, no one else is left to fulfill it. The people who have Jesus' attitudes are sent into the world as God's solution in order to shine for all to see.
This program is already assigned to that list.