This verse is a short saying that warns against criticizing a servant to his master.
“Do not slander a servant to his master”: The verb “slander” is related to the word “tongue” and has the sense of “gossip about” or “say bad things about” a person. “Criticize” (Good News Translation) is appropriate in this context. Scott gives the title “Talebearing” to this saying, and takes the verb in the narrower sense of informing the master about some particular thing the servant has done wrong; this also is possible in the context but not really required by the Hebrew. For “servant” see 17.2, where Revised Standard Version translates the same Hebrew word as “slave.” For “master” see 27.18.
“Lest he curse you, and you be held guilty”: “He” refers back to the servant in the previous line, not the master. The sense of “lest he . . .” is “if you do that, he might [or, he will] . . ..” To “curse you” is to “call down trouble on you” or “ask God to do something bad to you” (see comments on 20.20 and 26.2). The verb “be held guilty” means in this context that “you will bear the punishment for your action.” So New International Version says “you will pay for it,” New Jerusalem Bible and Good News Translation “you suffer for it,” and Contemporary English Version “you will be in trouble.”
Quoted with permission from Reyburn, William D. and Fry, Euan McG. A Handbook on Proverbs. (UBS Helps for Translators). New York: UBS, 2000. For this and other handbooks for translators see here .
