Jehoshaphat told the judges he appointed that they were judging not for man but for whom?

Answer: The LORD

Jehoshaphat set judges in Judah's fortified cities and warned them to judge carefully, for the LORD was with them in judgment.

“He appointed judges in the land, in each of the fortified cities of Judah. Then he said to the judges, “Consider carefully what you do, for you are not judging for man, but for the LORD, who is with you when you render judgment.”— 2 Chronicles 19:5-6 (BSB)