When Moshe set up the system of justice, he wanted men who had various qualities. He wanted men with understanding.
Devarim 1:13 - Provide yourselves men, wise and understanding and renowned to your tribes, and I will designate them your leaders."
But he did not find understanding people. He found judges with other qualities but not understanding.
I took the leaders of your tribes, Men wise and renowned (Devarim 1:15).
Rashi says: "But men of understanding I did not find. This qualification was one of the seven requirements which Yisro outlined to Moshe. [Moshe] found only three of them: righteous men, wise men, and men of renown".
Wonderful qualities! Fine upstanding people they were but not understanding.
Understanding people are hard to find.
Even for Moshe!