1 tn The traditional translation of “silver dross” (so KJV, ASV, NASB) never did make much sense because the parallel idea deals with hypocrisy – “fervent lips with an evil heart.” But silver dross would not be used over earthenware – instead it is discarded. Yet the MT clearly has “silver dross” (כֶּסֶף סִיגִים, kesef sigim). Ugaritic turned up a word spsg which means “glaze,” and this found a parallel in Hittite zapzaga[y]a. H. L. Ginsberg repointed the Hebrew text to k’sapsagim, “like glaze,” and this has been adopted by many commentators and recent English versions (e.g., NAB, NIV, NRSV, NLT). The final ם (mem) is then classified as enclitic. See, among others, K. L. Barker, “The Value of Ugaritic for Old Testament Studies,” BSac 133 (1976): 128-29.
2 tn The word translated “fervent” actually means “burning, glowing”; the LXX has “flattering lips” (as if from חָלַק [khalaq] rather than דָּלַק [dalaq]).
3 sn The analogy fits the second line very well. Glaze makes a vessel look beautiful and certainly different from the clay that it actually is. So is one who has evil intent (“heart”) but covers it with glowing speech.
