Solomon
Proverbs 13:17ESV·traditional attribution

A wicked messenger falls into trouble, but a faithful envoy brings healing.

Matthew Henry Presbyterian @wholebiblehenry

Here we have, 1. The ill consequences of betraying a trust. A wicked messenger, who, being sent to negotiate any business, is false to him that employed him, divulges his counsels, and so defeats his designs, cannot expect to prosper, but will certainly fall into some mischief or other, will be discovered and punished, since nothing is more hateful to God and man than the...

John Gill Reformed Baptist @doctorgill

A wicked messenger falleth into mischief,.... That does not do his errand right, nor deliver his message faithfully; such an one falls from the degree of honour in which he was into disgrace; he loses his master's favour that sent him; he is degraded from his post and office: he falls "by evil", or "into evil" (r); by the evil of sin, into the evil of punishment.

Jamieson-Fausset-Brown Reformed @jfbcommentary

A wicked--or, "unfaithful" messenger falleth into mischief--or, "by mischief," or "evil," and so his errand fails. Contrasted is the character of the faithful, whose faithfulness benefits others.