Charles Ellicott Commentary Matthew 5:13

"Ye are the salt of the earth: but if the salt have lost its savor, wherewith shall it be salted? it is thenceforth good for nothing, but to be cast out and trodden under foot of men." — Matthew 5:13 (ASV)

You are the salt of the earth — The words are spoken to the disciples in their ideal character, as the germ of a new Israel, called to a prophetic work, preserving the earth from moral putrescence and decay. The general reference to this antiseptic action of salt (as in Colossians 4:6, and possibly in the symbolic act of Elisha in 2 Kings 2:21) is enough to give an adequate meaning to the words, but the special reference to the sacrificial use of salt in Mark 9:49 (see the note on that verse) makes it probable enough that there was some allusion to that thought here as well.

If the salt has lost its flavour — The salt commonly used by the Jews in ancient times, as now, came from Jebel-Usdum, on the shores of the Dead Sea, and was known as the Salt of Sodom. Maundrell, the Eastern traveller (around A.D. 1690), reports that he found lumps of rock-salt there that had become partially flavourless, but I am not aware that this has been confirmed by recent travellers. Common salt, as is well known, will melt if exposed to moisture but does not lose its saltiness. The question is more curious than important and does not affect the ideal case represented in our Lord’s words.

With what shall it be salted? — The words imply a relative, if not an absolute, impossibility. If gifts, graces, blessings, a high calling, and a high work fail, what remains? The parable finds its interpretation in Hebrews 6:1-6.

To be trodden underfoot by men — The Talmud shows (according to Schottgen, commenting on this passage) that the salt that had become unfit for sacrificial use in the storehouse was sprinkled in wet weather on the slopes and steps of the temple to prevent the priests’ feet from slipping. We may accordingly see in our Lord’s words a possible reference to this practice.