You are the salt of the earth; but if salt has lost its taste, how can its saltiness be restored? It is no longer good for anything, but is thrown out and trampled under foot.
You are the light of the world. A city built on a hill cannot be hid. No one after lighting a lamp puts it under the bushel basket, but on the lampstand, and it gives light to all in the house. In the same way, let your light shine before others, so that they may see your good works and give glory to your Father in heaven. (Matthew 5:13-16, NRSV)
Salt and light represent what every Christian should be— a penetrating and illuminating influence, something both to be seen and felt, a power to attract and transform. Notice the—
I. Twofold Sphere
1. The Earth. “You are the salt of the earth.” The earth is the place of the curse, and may represent the heart of man as the seat of his affections and the source of his desires “Thy will be done in earth” (Matthew 6:10)—in the heart of man as in Heaven Purify the spring (2 Kings 2:21).
2. The World. “You are the light of the world.” The world here may mean the sphere of man’s mind and thought. Apart from the light of revelation, this is a world of spiritual darkness. “No light in them.”
II. Twofold Action
1. It Permeates Like Salt. Invisible, but effectual in its working. Must first get into touch with the corruptions of ungodliness before it can heal. It represents unconscious influence.
2. It Illuminates Like Light. This is something to be seen. The light is not something put on. It is the outcome of a flame kindled The Christian’s life is the light. The life is the light of men. If there is abundance of life there will be a brightness of light. A living Christ within will make a steady light without.
III. Twofold Nature
1. The salt must have savor. Salt is good, but savorless salt is good for nothing. The mere name and form without this is powerless. The savor is an emblem of the Holy Spirit. We may bear the name Christian and have the form of godliness, but without the Holy Spirit we are savorless salt, “good for nothing.” “Have salt in yourselves” (Mark 9:50). Salted with the fire of the Holy Spirit. It is the savor that is precious and powerful. “Be filled with the Spirit” (Ephesians 5:18).
2. The candle must have light. Here again the mere name and form are useless without the living flame. A candle must be lighted; it cannot light itself. God hath shined into our hearts, giving us the light. “Thou hast lighted my lamp, O Lord.”
IV. Twofold Purpose
1. To Salt the Earth. If Christians lose their savor, with which shall it be salted? If the world does not see Christ in the Christian, where will it see Him? If the ungodly don’t feel the power of Christ’s presence in the actions of His people, how will they feel it?
2. To Glorify the Father (v. 16). The light is to shine, not that men may praise the light, but that they may be led to trust and glorify the Father. Let your light so shine.
V. Twofold Hindrance
1. In Losing the Savor. “If the salt lose its savor, it is thenceforth good for nothing,” trodden under foot of men. Sad picture of a powerless Christian! A withered branch. Samson was savorless salt when the Spirit departed from him (Judges 16:20). Quench not the Spirit.
2. In Hiding the Light. If God has shined in our hearts, it is to give the light (2 Corinthians 4:6). Let it shine forth in a bold, steady testimony for Christ. The fear of man is often the bushel that hides the light, or the bed of selfish ease. Remember that a covered light may be suffocated.
(James Smith, Handfuls on Purpose)