Charles H. Spurgeon on Psalms 120:4

Sharp arrows of the mighty, with coals of juniper. The world's sin is the world's punishment. A correspondence is frequently observed between the transgression and the retribution... This law of correspondence seem to be here indicated. Similar figures are employed to express the offence and the punishment of the wicked. "They bend their tongue like a bow for lies." "Who whet their tongue like a sword, and bend their bows to shoot in secret at the perfect." But let the slanderer be upon his guard. There is another bow besides that in his possession. The arrows are sharp and burning; and when they are sent from the bow by the arm of Omnipotence, nothing can resist their force, and in mortal agony his enemies bite the dust. "He hath bent his bow, and made it ready. He hath also prepared for him the instruments of death: He ordaineth his arrows against the persecutors." "God shall shoot at them with an arrow; suddenly shall they be wounded; so shall they make their own tongue fall upon themselves." This train of thought is also pursued in the illustration of fire. James compares the tongue of slander to fire. "And the tongue is a fire, a world of iniquity: so is the tongue among the members, that it defileth the whole body, and setteth on fire the course of nature; and it is set on fire of hell." Such is the tongue, and here is the punishment: "Coals of juniper, "remarkable for their long retention of heat. And yet what a feeble illustration of the wrath of God, which burns down to the lowest hell! "His lips are full of indignation, and his tongue as a devouring fire." Liars are excluded from heaven by a special enactment of the Sovereign; and all of them "shall have their part in the lake which burneth with fire and brimstone, which is the second death." "Who among us shall dwell with the devouring fire? Who among us shall dwell with everlasting burnings?" With what solemn awe should we not cry out to the Lord, "Gather not my soul with sinners, nor my life with bloody mens!" —N. McMichael, in "The Pilgrim Psalms," 1860.