Rashi on Exodus 18:21/רש"י על שמות י״ח:כ״א

1ואתה תחזה MOREOVER THOU SHALT PROVIDE through the Holy Spirit that is upon thee (Mekhilta),

2אנשי חיל MEN OF ABILITY (but חיל may mean “wealth” and in this sense the words would mean) — rich men who will not need to flatter or to show favour (cf. Mekhilta).

3אנשי אמת MEN OF TRUTH — These are people commanding confidence (Mekhilta); who are deserving that one should rely upon their words — appoint these as judges because on account of this their words will be listened to.

4שנאי בצע HATING LUCRE — men who hate (pay no regard to) their property when it is to be made the matter of a law-suit (Mekhilta), in accordance with what we say: Any judge from whom one has to wring the money he owes only by means of a law-suit is no fitting judge (Bava Batra 58b).

5שרי אלפים OFFICERS OF THOUSANDS — there were six hundred such officers for the six hundred thousand men of Israel.

6שרי מאות OFFICERS OF HUNDREDS — there were six thousand of them.

7שרי חמשים OFFICERS OF FIFTIES — twelve thousand.

8שרי עשרת OFFICERS OF TENS — sixty thousand (Mekhilta, Sanhedrin 18a).