The Lord Jesus, in speaking of the believers’ influence on the world, said that we are the salt of the earth and the light of the world (vv. 13-14). There is a difference between the earth and the world. The earth was created by God, whereas the world came into being through the corruption of the earth. We are salt to the God-created earth and light to the Satan-corrupted world.
The first part of verse 13 says, “You are the salt of the earth.” Salt, by nature, is an element that kills and eliminates the germs of corruption. To the corrupted earth the believers who live in the reality of the kingdom of the heavens are such an element, keeping the earth from being fully corrupted. This means that the believers exercise influence over the God-created earth. The believers, as salt with its killing and preserving function, bring the earth back to its original condition and preserve it in that condition. Hence, the function of the believers is to preserve what God has created. As the salt of the earth, we have the function of killing germs and eliminating rottenness, that is, of preserving things in their original condition or of bringing them back to their God-created condition. Eventually, when the millennial kingdom comes, all the germs on the earth will be utterly killed, and the whole earth will be regained by Christ and brought back to its God-created condition. In this age, wherever the believers are, they should exercise a salting influence over those around them.
Regarding the earth, there is the need of salt; regarding the world, there is the need of light. Darkness is not related to the earth but to the world. The world refers to human society, Satan’s system. The dark human society of the world, the satanic system, needs light. Therefore, the Lord Jesus said, “You are the light of the world” (v. 14a). The believers are the light that effaces the world’s darkness.
In verses 14 and 15 the Lord Jesus said, “It is impossible for a city situated upon a mountain to be hidden. Nor do men light a lamp and place it under the bushel, but on the lampstand; and it shines to all who are in the house.” Here the Lord spoke regarding the believers’ outward and inward shining. The light as a city on a mountain shines outwardly upon those outside, whereas the lighted lamp on the lampstand shines inwardly to those who are in the house. As the city, the light shines upon people, but as the lamp in the house, the light shines into people. This indicates that our influence over others should not merely be outward but also inward. The outward shining is general, but the inward shining is particular. A city situated on the mountain has a general outward shining, but a lamp on a lampstand has a particular inward shining. This inward shining penetrates the inward being of others and convinces them.
Eventually, both aspects of our shining will give glory to the Father. Verse 16 says, “In the same way, let your light shine before men, so that they may see your good works and glorify your Father who is in the heavens.” Good works constitute the behavior and living of the believers who live in the reality of the kingdom of the heavens. Through such works men can see God and be brought to Him. Our shining glorifies the Father because it expresses God. Glory is God expressed. When we express God in our behavior and good works, men see God and give the glory to God. If we are such a shining light, God will be expressed in our shining, and all those around us will see glory, God expressed. When others see God in our shining, it is a glory to God. As a city without and as a lamp within, we shine to express God, to let God have the glory in the eyes of others.