1 tn The term “as” is not in the Hebrew text, but is supplied in the translation to clarify the comparison.
2 tn BDB classifies the verb in the first colon as a Qal apocopated jussive of I חָדָה (khadah, “to grow sharp”; BDB 292 s.v.), and the verb in the second half of the verse (יַחַד, yakhad) as a Hiphil apocopated jussive. The difference would be: “let iron by means of iron grow sharp, and let a man sharpen the countenance of his friend.” But it makes more sense to take them both as Hiphil forms, the first being in pause. Other suggestions have been put forward for the meaning of the word, but the verb “sharpens” fits the context the best, and is followed by most English versions. The verb may be a shortened form of the imperfect rather than a jussive.
3 tn Heb “and a man,” although the context does not indicate this should be limited to males only.
4 tn Heb “sharpens the face of his friend.” The use of the word “face” (cf. KJV, ASV “countenance”) would here emphasize that it is the personality or character that is being sharpened. Constructive criticism sharpens character. Use of the wits in interaction that makes two people sharp as a razor (W. McKane, Proverbs [OTL], 615); another example, from the Talmud, is that of two students sharpening each other in the study of the Torah (b. Ta’anit 7a).