Solomon
Proverbs 30:10ESV·traditional attribution

Do not slander a servant to his master, lest he curse you, and you be held guilty.

Matthew Henry Presbyterian @wholebiblehenry

Here is, I. A caution not to abuse other people's servants any more than our own, nor to make mischief between them and their masters, for it is an ill office, invidious, and what will make a man odious, Pro 30:10. Consider, 1.

Commenting on Proverbs 30:10-14

John Gill Reformed Baptist @doctorgill

Accuse not a servant unto his master,.... Wrongly, rashly, and without any foundation, nor for any trifling thing; unless it be in a case of moment and importance, when his master's business is sadly neglected, or he is injured in his property by him: especially care should be taken not to calumniate a servant, to abuse him with the tongue, as the word (g) signifies...

Jamieson-Fausset-Brown Reformed @jfbcommentary

Accuse not--Slander not (Psa 10:7). curse . . . guilty--lest, however lowly, he be exasperated to turn on thee, and your guilt be made to appear.