5:14 light of the world Recalls Israel’s role as a light to the nations (Isa 42:6; 49:6). In John, Jesus describes Himself as the light of the world (John 8:12; 9:5).
Barry, J. D., Mangum, D., Brown, D. R., Heiser, M. S., Custis, M., Ritzema, E., … Bomar, D. (2012, 2016).
Faithlife Study Bible (Mt 5:14). Bellingham, WA: Lexham Press.
5:14–16 You are the light of the world is an allusion to Is 9:1–2; 42:6; 49:6—texts that describe the ministry of Messiah, Servant of the Lord. This indicates that Jesus’s disciples are to be extensions of his ministry, carrying salvation to the ends of the earth. Such ministry is intrinsic to true discipleship. A disciple should no more conceal his righteousness or the gospel message than a glowing city should douse its light at night. The reference to giving light for all combines with the reference to “the world” to show that Christ’s ministry is intended for all people. This anticipates the Great Commission of Mt 28:18–20.
Jesus’s words make clear that the disciple is not the ultimate author of his good works. If the disciple were the author of his good works, he would justly receive praise. However, Jesus taught that only the Father in heaven is to be praised for a disciple’s good works, for he is the true source of such works (see note at v. 6). This must not be overlooked. The righteousness demanded by the Sermon on the Mount is a divine gift that God imparts to Jesus’s followers.
Stein, R. H. (2017).
Differences in the Gospels. In E. A. Blum & T. Wax (Eds.),
CSB Study Bible: Notes (p. 1507). Nashville, TN: Holman Bible Publishers.