When Jesus speaks of salt losing its salty quality, He’s referring to the method of mining salt unique to that period and region. People would harvest salt from either the Dead Sea or from the salt pans, and in those salt pans the water evaporated. In that process, the pure salt would leech out, leaving a residue of other minerals and causing the salt to “lose” its saltiness. So, Jesus poses the question to His disciples, “What good will you be if you lose your saltiness—if you succumb to the things that leech the salt out of your lives?”
Many have described Christ’s words in Mark 9:49–50 as being among the New Testament’s most challenging passages. They read,
Everyone will be salted with fire. Salt is good, but if the salt has lost its saltiness, how will you make it salty again? Have salt in yourselves, and be at peace with one another.
These verses reinforce a familiar biblical theme: following Jesus is a serious business. Anybody who views Christianity as some kind of esoteric philosophical journey—a sort of crutch for the inept—must reckon with Jesus’ own claims. The call to following Him involves self-denial and suffering (Mark 8:34).
Jesus further clarifies the seriousness of discipleship in the verses immediately preceding the text in view (Mark 9:42–48). Warning against sin’s dangers, He doesn’t suggest that we negotiate with sin, trying to reconcile our sinful propensities with discipleship’s demands. Rather, He calls for its total eradication. We don’t toy with sin; we put it to death (Col. 3:5).
It’s clear that Jesus deals here with weighty truths. And it’s against the backdrop of verse 48 (in which He describes hell as a place where the “worm does not die and the fire is not quenched”) that His puzzling teaching on salt appears. With the costliness of discipleship and the picture of fire fixed in His disciples’ minds, Jesus asserts, “Everyone will be salted with fire.” How should we understand this peculiar phrase?
The Old Testament Background
The sacrificial system in the Old Testament is a good place to begin. It would’ve been familiar territory for Jesus and His audience. Establishing the design for grain offerings in Israel, God had made the following provision: “You shall season all your grain offerings with salt. You shall not let the salt of the covenant with your God be missing from your grain offering; with all your offerings you shall offer salt” (Lev. 2:13).
Further, these seasoned offerings were burnt offerings; they were consumed on the altar. In this sense, these Old Testament sacrifices were complete and irrevocable. Jesus appears to be reaching back to this practice, collating the pictures of fire and salt, to remind His followers that discipleship will involve a process whereby they’re “salted.” When they offer themselves to Christ’s cause, they will undergo a refining process, their allegiance to Him being complete and irrevocable.
Other places in the New Testament affirm this idea. In 1 Corinthians 3, Paul describes a similar refining process:
No one can lay a foundation other than that which is laid, which is Jesus Christ. Now if anyone builds on the foundation with gold, silver, precious stones, wood, hay, straw—each one’s work will become manifest, for the Day will disclose it, because it will be revealed by fire, and the fire will test what sort of work each one has done. (1 Cor. 3:11–13).