tnHeb “the words of the Lord are pure words,” i.e., untainted by falsehood or deception (in contrast to the flattery of the evildoers, v. 2).
18
tnHeb “[like] silver purified in a furnace of [i.e., “on”] the ground, refined seven times.” The singular participle מְזֻקָּק (mézuqqaq, “refined”) modifies “silver.” The number seven is used rhetorically to express the thorough nature of the action. For other rhetorical/figurative uses of שִׁבְעָתָיִם (shiv’atayim, “seven times”), see Gen 4:15, 24; Ps 79:12; Prov 6:31; Isa 30:26.