The light of the world (5:14–16). Jesus’ disciples are not only “the salt of the earth” but also “the light of the world.” The light metaphor continues the salt metaphor and takes it one step further to illustrate Jesus’ point. “Light” is an important theme in Scripture, normally emphasizing the removal of darkness in the unfolding of biblical history and theology. The literal contrast between physical light and darkness provokes a profound metaphorical contrast between metaphysical good and evil, God and evil forces, believers and unbelievers. Jesus later declares that he is “the light of the world” (John 8:12; 9:5), who has come as the light that enlightens all people (1:4–14), so that those believing in him will no longer be in darkness (12:46).
In the same way as Jesus’ life and message of salvation bring light to those in darkness (Matt. 4:15–16), his disciples are a living demonstration of the arrival of the kingdom of heaven. The light of revelation from God that accompanies Jesus’ announcement of the kingdom is not just carried by his disciples; they are that light (Matt. 5:14–16; cf. Eph. 5:8; Phil. 2:15).
Jesus continues the proverbial “impossible” language he used in the salt metaphor by stating that “a city on a hill cannot be hidden,” and “neither do people light a lamp and put it under a bowl.” The city to which Jesus refers may be Jerusalem, which sits on Mount Zion, since Israel with Jerusalem as the holy city was considered light to the world (Isa. 2:2–5; 42:6; 49:6). But since Jesus is now in Galilee near Capernaum, he may be using a local city as his illustration, because he often used images from his surroundings to illustrate his teaching. In either case, it is impossible to hide a city located on a hill.
The lamp used in a typical Palestinian home was a partially closed reservoir made of clay. It had a hole on top to pour oil in and a spout on one end into which a wick of flax or cotton was set. It was a fairly small lamp, which gave off only a modest light; thus, to give maximum illumination it was placed on a lampstand. Since many Jewish homes were often modest one-room structures, such an elevated lamp could give light to everyone in the house. Lamps were essential for finding one’s way in enclosed areas during the night and were placed under a measuring bowl only to extinguish the light (cf. m. Šabb. 16.1).
Jesus’ disciples are called to be the light of the world. They cannot be hidden, for their very nature, the kingdom life within them, is living testimony to those in the world who do not yet have that light. Their good works are produced by the light and life that come from God. It is not of their own making, because those who see them in action will glorify not them but their “Father in heaven” (cf. the motive of the religious leaders in 6:1). The title “Father” is used in Matthew here for the first time, introducing the special relationship that exists between God and Jesus’ disciples. Jesus has been declared to be the beloved Son (3:17), and now those who have received the kingdom light are children of the heavenly Father as well (cf. John 1:7–13).
Jesus’ disciples possess kingdom life, which produces good deeds from a changed life. Bearing the light of the gospel in both message and life will bring people to know that the kingdom of heaven truly is in the world, and they will glorify their heavenly Father. The Beatitudes hinted at this direction, but the metaphors of salt and light are the first explicit indication that the presence of the kingdom produces changed lives.