Samin Nosrat, in her terrific culinary book Salt, Fat, Acid, Heat, writes,
James Beard, the father of modern American cookery, once asked, “Where would we be without salt?” I know the answer: adrift in a sea of blandness. If only one lesson of this book stays with you, let it be this: salt has a greater impact on flavor than any other ingredient.
Nosrat asserts, “In fact, we’re hardwired to crave salt to ensure we get enough of it.”
Christians understand “the salt of the earth” as one of the master metaphors of our relationship to wider human society. When the church’s witness with respect to the unbelieving world is discussed, our calling as “salt and light” is often one of the first identifications to be invoked, and rightly so.
The Lord Jesus designates his disciples as the “salt of the earth” and “light of the world” (Matt. 5:13–14) immediately following the mountaintop benediction he pronounces upon them in the Beatitudes (vv. 1–12). If the Beatitudes are the kingdom constitution, then being “salt and light” is how the citizens of the kingdom are to walk in holy distinction from the course of a world that has its own charter centered in the sinful self with its deceitful desires (cf. Eph. 2:2; 4:22).
Because it’s so foundational, understanding the nature and purpose of the image of “salt” in Matthew 5:13 is vital. The church fulfills her calling as “the salt of the earth” in serving as the taste of the kingdom of heaven, and that in doing so the body of Christ invites the world to the feast of life in the kingdom.
“Salt” in Matthew 5 isn’t referring to the flavor and seasoning believers bring to human life and society. It’s rather to be taken as signifying the beginnings of the heavenly banquet whose foretaste is found in the church of Christ. Like the pomegranates, figs, and grapes brought back to Israel in the wilderness by the spies (Num. 13:23, 26), believers’ communion in life as the “salt of the earth” is a proleptic experience of the fullness of the age to come.
Taste of the Coming Age
There are various functions salt serves, but the particular aspect of the salt to which Jesus is referring is its taste: “If the salt has lost its flavor . . .” (μωρανθῇ).
The body of Christ invites the world to the feast of life in the kingdom.
If the danger is for the salt to become tasteless or flavorless, then by implication the Lord is commanding the disciples to keep their distinct flavor. And what is that flavor? To continue to walk in the way of blessedness as unpacked in verses 1–12. This is the way to exhibit the “salt life” of God’s redemptive kingdom. Don Garlington helpfully writes,
Because they exhibit the qualities signaled by the indicatives of Matt 5:3–12, the disciples are proof positive that the kingdom is a reality in the world. It is just in their capacity as “the poor in spirit,” “those who mourn,” “the meek,” “those who hunger and thirst for righteousness,” “the merciful,” “the pure in heart,” “the peacemakers,” and the “persecuted” that Jesus’ followers are salt and light and, as such, the eschatological reality of the kingdom is actualized in their persons as the subjects of his reign.
Thus, Jesus isn’t referring to salt penetrating or permeating the earth so that his disciples show forth a “sweetening and wholesome influence.” Instead, the salt represents the savor of the age to come, and the disciples walking in the ways of the kingdom of God are calling those from the kingdom of this world to leave the bitter course of the place of darkness (cf. Matt. 4:15–16).
There’s an implicit invitation contained in the “salt of the earth” image: as the nations are being discipled (28:19), they share in the “salt life” of the new order inaugurated in Christ. Rudolf Schnackenburg concludes, “Together with the image of the lamp, it [the salt] is an appeal to the community of disciples to bear witness to the gospel, in the midst of a world still averse to it, by living a life in conformity with Jesus’ instructions.”
Furthermore, the flavor of the salt will be to practice the righteousness that exceeds that of the scribes and Pharisees (5:20). This fits with one of the larger themes in the Sermon on the Mount: the kingdom that Christ is inaugurating stands in continuity with “the Law and the Prophets”—as Jesus comes not to abolish but to fulfill them (v. 17); at the same time, this kingdom supersedes the prior expression of God’s reign as revealed at Sinai (cf. vv. 38–42).
The warning of Jesus concerning the salt may be the most significant clue concerning the purpose of this image. There’s a double entendre in μωρανθῇ: it’s both “losing flavor” and “becoming foolish.” Paul writes, “Claiming to be wise, they became fools [ἐμωράνθησαν].” Robert Gundry, in a thorough study of “fools” and “foolish” in Matthew, concludes that “fool(ish)” is always associated with those who are outside the kingdom of heaven. It’s possible for those who are called to be salt to lose flavor in severing themselves from Christ and the wisdom revealed in him (cf. Gal. 5:4; 2 John 8).
Here the Lord appears to be hinting at the failure of Israel to maintain fidelity to the covenant. The order of the Beatitudes and the warning given in Matthew 5:13 reflects the prayer of restoration of the psalmist: “Let me hear what God the LORD will speak, for he will speak peace to his people, to his saints; but let them not turn back to folly” (Ps. 85:8).
“If the salt has lost its taste, how shall its saltiness be restored? It is no longer good for anything except to be thrown out and trampled under people’s feet” (Matt. 5:13). This serves to alert the disciples (the new Israel) to vigilance and also as a harbinger of what will become of the old Israel that rejects Christ and his kingdom. John the Baptist had earlier announced, “Even now the axe is laid to the root of the trees” (3:10). Jesus prophesies concerning the unbelieving Jerusalem and her inhabitants, who have definitively rejected his words: “They will fall by the edge of the sword and be led captive among all nations, and Jerusalem will be trampled underfoot by the Gentiles, until the times of the Gentiles are fulfilled” (Luke 21:24).
Later in Matthew, Jesus teaches in parables and likens the kingdom of heaven to a “king who gave a wedding feast for his son, and sent his servant to call those who were invited to the wedding feast, but they would not come” (Matt. 22:2–3). Some are foolish (δὲ ἐξ αὐτῶν ἦσαν μωραί) in failing to be ready to meet the bridegroom (25:2). Those who fail to share in the joy of the messianic coming are culpably foolish.
But though the original parties reject the invitation, the wedding feast will still be held:
“The wedding feast is ready, but those invited were not worthy. Go therefore to the main roads and invite to the wedding feast as many as you can find.” And those servants went out into the roads and gathered all whom they found, both bad and good. So the wedding hall was filled with guests. (22:8–10)
The salt which stands for the flavor and fullness of the kingdom of God will be tasted by many who are far off (cf. Rom. 15:20–21; Eph. 2:17).
Setting the Kingdom Table
In my estimation, it’s best to take salt in Matthew 5:13 as an example of metonymy: “A figure of speech consisting of the use of the name of one thing for that of another of which it is an attribute or with which it is associated.”
For example, God’s “right hand” stands for his incontestable power (cf. Pss. 98:1; 108:6). To hear of the Lord’s “right hand” is to be summoned to consider the royal strength and sovereignty of the Most High.
Those who fail to share in the joy of the messianic coming are culpably foolish.
“Salt,” rhetorically speaking, opens the door to the setting of the kingdom table: “Wisdom has built her house; she has hewn her seven pillars. She has slaughtered her beasts, she has mixed her wine; she has also set her table” (Prov. 9:1–2). Jesus has already in Matthew 5 introduced the image of appetite and provision: “Blessed are those who hunger and thirst for righteousness, for they shall be satisfied” (v. 6). Salt according to the terms of this “language game” isn’t found in the cupboard or in the shaker, waiting to be dispensed; instead, it belongs to the flavor ready to be tasted on the chef’s table—that is, already present in the life of the new creation reign of God in Christ.
If indeed the “salt of the earth” metaphor is to be taken as the call for the church’s continued testimony to and participation in the flavor of the kingdom of heaven, we should be wary of appropriating this verse as endorsing the idea that the church qua church exists to promote general human flourishing.
Cultural and societal influence cannot be used as a barometer of the “saltiness” enjoined in Matthew 5:13. Inasmuch as the church is faithful in “making disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that [Jesus has] commanded [us]” (28:19–20), the unparalleled flavor of the kingdom of God, with the Savior-King himself, will be present to the end of the age.