Pro 26:23
The proverbs next following treat of a cognate theme, hypocrisy (the art of dissembling), which, under a shining [gleissen] exterior, conceals hatred and destruction: 23 Dross of silver spread over an earthen vessel - Lips glowing with love and a base heart.
Dross of silver is the so-called glätte (French, litharge), a combination of lead and oxygen, which, in the old process of producing silver, was separated (Luther: silberschaum, i.e., the silver litharge; Lat. spuma argenti, having the appearance of foam). It is still used to glaze over potter’s ware, which here (Greek, κέραμος) is briefly called חרשׂ for כּלי חרשׂ; for the vessel is better in appearance than the mere potsherd. The glossing of the earthenware is called צפּה על־חרשׂ, which is applicable to any kind of covering (צפּה, R. צף, to spread or lay out broad) of a less costly material with that which is more precious. 23a contains the figure, and 23b its subscription: שׂפתים דּלקים ולב רע. Thus, with the taking away of the Makkeph after Codd., to be punctuated: burning lips, and therewith a base heart; burning, that is, with the fire of love (Meîri, אשׁ החשׁק), while yet the assurances of friendship, sealed by ardent kisses, serve only to mask a far different heart. The lxx translate דלקים [burning] by λεῖα, and thus have read חלקים [smooth], which Hitzig without reason prefers; burning lips (Jerome, incorrectly: tumentia; Luther, after Deu 32:33, חמת: Gifftiger mund = a poisonous mouth) are just flattering, and at the same time hypocritical lips. Regarding שׂפתים as masc., vid., p. 85; לב רע means, at Pro 25:20, animus maestus; here, inimicus. The figure is excellent: one may regard a vessel with the silver gloss as silver, and it is still earthen; and that also which gives forth the silver glance is not silver, but only the refuse of silver. Both are suitable to the comparison: the lips only glitter, the heart is false (Heidenheim).