Albert Barnes Commentary Psalms 120:4

"Sharp arrows of the mighty, With coals of juniper." — Psalms 120:4 (ASV)

Sharp arrows of the mighty — This is an answer to the question in (Psalms 120:3). The consequence — the effect — of such a use of the tongue must be like sharp and piercing arrows, or like intensely burning coals. The sharp arrows of the mighty are the arrows of the warrior — as war was conducted mainly by bows and arrows. Those arrows were, of course, sharpened to make them piercing, penetrating, more deadly.

With coals of juniper — On the word here rendered “juniper,” see the notes at (Job 30:4). The idea here is, that coals made from that would be intensely hot, and would cause severer pain than if made from other wood. The word refers to a species of broom or shrub growing in the deserts of Arabia, with yellowish flowers and a bitter root. See “Robinson’s Biblical Researches,” vol. i., p. 299. Burchardt says that he found the Bedouin of Sinai burning the roots into coal, and says that they make the best charcoal, and throw out the most intense heat. The shrub sometimes grows so large as to furnish a shade to those exposed to the heat of the sun in the desert, (1 Kings 19:4); “Land and the Book” (Thomson), vol. ii., pp. 438, 439. The illustration given below will give an idea of this plant.