Solomon
Proverbs 25:13ESV·traditional attribution

Like the cold of snow in the time of harvest is a faithful messenger to those who send him; he refreshes the soul of his masters.

Matthew Henry Presbyterian @wholebiblehenry

See here, 1. What ought to be the care of a servant, the meanest that is sent on an errand and entrusted with any business, much more the greatest, the agent and ambassador of a prince; he ought to be faithful to him that sends him, and to see to it that he do not, by mistake or with design, falsify his trust, and that...

John Gill Reformed Baptist @doctorgill

As the cold of snow in the time of harvest,.... As water as cold as snow; or as a breeze of air, such as in a time of snow; and so Jarchi, "as the cold of the days of snow, which a man desires in summer, and not snow simply, for snow itself is not good in the time of harvest;'' see Pro 24:1.

Jamieson-Fausset-Brown Reformed @jfbcommentary

Snow from mountains was used to cool drinks; so refreshing is a faithful messenger (Pro 13:17).