Salt is of great importance to man. It makes savory what without it would be insipid. It checks the growth of nature in the vegetable kingdom; it preserves, too, from corruption and decay, what belongs to the animal kingdom.
Of its savory properties Job speaks (6:6). To its power in destroying the growth of nature Moses and the Prophets bear witness (Deut. 29:23; Jer. 17:6; Ezek. 47:11); and Abimelech's action in sowing the city of Shechem with salt (Judg. 9:45), shows us that Israel were well acquainted with its influence on vegetation. But not less marked is its action on that which belongs to the animal kingdom, preserving what is subjected to its influence from that corruption to which otherwise it would as suredly turn.
Now as salt acts in the realm of nature, so does grace in spiritual matters. It savors; it checks the outflow of nature from man. It is preservative, too, in its action from corruption.
Under the law the meat-offering was to be salted, typical of the Lord Jesus in His life on earth, in whom grace acted constantly (Lev. 2:13). With all their offerings they were to offer salt. Hence a " covenant of salt" was a term Israel well understood (Num. 18:19; 2 Chron. 13:5), meaning that such a covenant should never be broken, no element of corruption should enter into it, for it would last forever. Of that character was the provision God made for the support of Aaron and his house. Of that same character was the Lord's engagement to David and his sons.
In the New Testament the figurative meaning of salt, as illustrative of grace in its savoring and preservative action, is met with more than once. The disciples were the " salt of the earth" (Matt. 5:13). But, as the Lord reminded them, salt is useless, if once it has lost its savor. So they would be of no use as salt, unless grace was really in them. What then man in nature has not, what the earth viewed morally does not possess, that the disciples were, and should be careful to continue to be. They were not merely salt for the earth, but the salt of the earth. And having salt in themselves, the working of nature would be checked, and they would have peace one with another (Mark 9:50). Moreover, that preservative and savoring character of grace would be felt, if their speech was always with grace, seasoned with salt (Col. 4:6). They would know how to answer every man, and no corrupt communication would proceed out of their mouth, but only that which was good to the use of edifying, that it might minister grace to the hearer (Eph. 4:29). Moreover, the preservative character of grace would characterize all God's people, " for every sacrifice shall be salted with salt."
But there is another statement of the Lord preserved only in one Gospel, that of Mark and that statement, to which we now draw attention, is most solemn in its character, and universal in its application. " Every one shall be salted with fire:" for as salt preserves things in the animal kingdom, so the fire of judgment will act on men. It will not consume them so as to terminate their existence, but burning up all that is perishable of men and their works (1 Cor. 3:13-15), will leave that which never can decay. To have one's works tried by fire is a solemn consideration for God's saints. To be salted with fire is a dreadful prospect for the wicked. And in connection with these latter, it should be remarked, the Lord brings in, Their worm dieth not, and the fire is not quenched; for every one shall be salted with fire " (Mark 9:48,49). Even in things of nature in the animal frame, there is a residuum, which the fire does not consume. But after burning up all that is consumable, the fire dies out. Now it will not be so in the other world; all that can perish will assuredly perish, but the wicked will never cease to exist, and the fire will never be extinguished.