(B.T. Vol. N5, p. 86-87.)
The Lord had laid down in vers. 5-9 the distinctive moral qualities suited to the kingdom of the heavens, with the supplemental blessednesses in sufferings (10-12). He now proceeds to state definitely their position here below according to His mind. The first is given in ver. 13, answering to righteousness, as we saw in the earlier qualities He endorses; the second in 14-16, answering to the outgoing energy of grace, remains for its separate notice in due season.
"Ye are the salt of the earth; but if the salt lose its savour, wherewith shall it be salted? It availeth for nothing any more but to be cast without and trodden under foot of men" (ver. 13).
The disciples were familiar with salt not only in ordinary life but in the oblation to Jehovah, "the salt of the covenant of thy God": "with all thine offerings thou shalt offer salt" (Lev. 2:13).
And so we read of "a covenant of salt": as expressive figuratively of what was to be preserved inviolate and unchanging (Num. 18:19; 2 Chron. 13:5). Accordingly the Lord, in Mark 9:49-50, declares that "every one shall be salted with fire, and every sacrifice shall be salted with salt. Salt [is] good; but if the salt become saltless wherewith will ye season it? Have salt in yourselves, and be at peace one with another."
If fire represents God's avenging judgment of evil, salt does no less clearly His preserving power in relation with Himself. For, as the Lord lets us know, the figures of the law are now by and in Him translated from the past shadows into present and everlasting realities. There is therefore a necessary dealing with "everyone" because all are ruined by sin. Faith bows to this now, as unbelief braves the warning to find it solemnly true and too late vindicated for eternity before the great white throne, and the unquenchable fire that follows. But as grace sent the Saviour to bear God's unsparing judgment when He made Jesus on the cross sin for us, so the believer judges himself all the more when he recognises in Him that suffered without the gate the true and divine sin-offering, consumed to ashes without the camp; Whose blood enters in all its value the holy of holies, and entitles himself boldly to approach even there, with a true heart in full assurance of faith, having the heart sprinkled from a wicked conscience, and the body washed with pure water.
He then, there, and thus was salted with fire in a way of absolute perfection as none other could be, as those who reject Him must be in the lake which burneth with fire and brimstone, which is the second death. But all who believe enjoy the full efficacy of that fire of God which He endured for our sins, whilst given to judge ourselves as in the sight of God and to reckon ourselves dead with Him to sin but alive to God in Christ Jesus; for he that died is justified from sin as well as sins. We have also the privilege of "every sacrifice salted with salt." It is not only that "our God is a consuming fire" against every evil thing, every inconsistency with relationship to Him and with His nature; but as offered to God, our bodies even as a living sacrifice, we know and have the seasoning with salt that we may be kept pure and incorrupt, abhorring any working of flesh as vile and condemned in Christ's death.
The disciples had yet to learn that wondrous and mighty sacrifice of His; but here they find themselves set in the only position which suited Him, and them too associated with Him. Its moral nature, not only inwardly but publicly, is here conveyed by the words. "Ye are the salt of the earth." To the Son as to the Father anything but this pure and purifying or at least preservative savour was intolerable for the kingdom of the heavens which they were to enter on the earth. The law, as we are told, made nothing perfect. And Moses, in view of Israel's hardheartedness, allowed what could not be when God was revealed in a Son. In that divine light He looks for suitability to His holiness. How it was to be made good in them they did not yet know; for the discourses on the mount did not unfold redemption nor yet the new birth. But there could be no doubt that this was the plain and certain expression of the place in which the Lord set His own.
Let it be noticed that they, and only they, and they emphatically, were "the salt of the earth." The Lord does not say the salt "of the world." This will come for fuller elucidation when we consider what was meant by their being "the light of the world," not of the earth. But when thus distinguished as here, we may remark now in pointing out the force of our text, that "the earth" means that ordered scene where God had dealings beyond other parts. It was then as of old where Israel was set; as it was about to be enlarged by the outward profession of His name far beyond the land of Palestine. The Lord accordingly begins with that position of conserving purity, alike privilege and responsibility. "Ye are the salt of the earth." Less or other than this was unrecognisable since He, the Son, came and called into association with Himself. The life He communicated to the believer, and the redemption He would accomplish for his sins, would be explained fully in its season. But here He shows what consisted with the Father, as well as the kingdom He would establish.
But He adds words — most grave words — "If the salt lose its savour, wherewith shall it be salted?" Profession there would be, and an excellent thing it is, if it be a heart testimony to God, true not only in word but in deed. Here, at the beginning and still more clearly at the end of His communications the Lord prepares us to expect what soon and increasingly became evident how hollow and false it was to become; and He intimated by His question and comment that the true and holy savour if once lost would be irreparable. Whatever grace might work individually, or with a few here and there, the pure position cannot be restored. Salt is itself. Nothing outside can give the saltness that disappears. Wherewith shall it be salted?
He goes farther, and pronounces its unfitness even for the useful purpose of fertilising supplied by that which is most offensive. Saltless salt is unavailing even to manure the earth. It is only fit to be thrown outside, and trodden under foot of men. And so it will be, as it has been. When Christianity vanishes and only a savourless Christendom remains, men have trodden it down as more worthless than Judaism or even Gentilism, and the more insufferable as so much prouder and more persecuting. And so it will be when the final blows come for Babylon; and the powers which once had their illicit commerce with her shall hate the harlot, and make her desolate and naked, and eat her flesh and burn her with fire. Not only is God strong in judging her, but she shall be trodden under foot of indignant men.