1. The first of the four clauses relates to the third, the second to the fourth, by alternate parallelism. The sense is: They are as keen after idols as if their propensity was "graven with an iron pen (Job 19:24) on their hearts," or as if it were sanctioned by a law "inscribed with a diamond point" on their altars. The names of their gods used to be written on "the horns of the altars" (Ac 17:23). As the clause "on their hearts" refers to their inward propensity, so "on . . . altars," the outward exhibition of it. Others refer "on the horns of . . . altars" to their staining them with the blood of victims, in imitation of the Levitical precept (Ex 29:12; Le 4:7, 18), but "written . . . graven," would thus be inappropriate.