(from Ramban’s Commentary on the Torah)
MEN OF ‘CHAYIL.’ This means men who are capable of leading a great multitude of people. Every assembly and gathering is called chayil, and it does not apply only to soldiers going forth to war. Thus it is said [of the dry bones that Ezekiel resurrected], a great ‘chayil’ (host) (Ezekiel 37:10). Of the locusts it is said, My great ‘chayil’ (army) (Joel 2:25). Of wealth it is stated, My power and the might of my hand hath gotten this ‘chayil’ (wealth) (Deuteronomy 8:17); they carry upon the shoulders of young asses ‘chayaleihem’ (their riches).105Isaiah 30:6. Of fruits it is said, the fig-tree and the vine do yield ‘cheilam’ (their strength).106Joel 2:22. Thus an ish chayil in the administration of justice is one who is wise, alert, and fair; in war, an ish chayil is one who is strong, alert, and who knows the art of arraying forces in battle. A woman also is an eisheth chayil (a woman of valor)107Proverbs 31:10. when she is alert and knows how to conduct the management of a home.
Jethro thus spoke in general and in particular. [In general], he told Moses to select people with powers of leadership in the administration of justice for this great people. In particular, they should be such as fear G-d, men of truth, hating unjust gain, for it is impossible for them to be “men of chayil” in judgment, without these qualities. It was not necessary for him to mention that they must be wise and understanding, for it is clear that these qualities are included in the term “men of chayil.” Further on, when it says, And Moses chose men of ‘chayil,’108Further, Verse 25. everything is already included — i.e., that they were G-d-fearing, men who hated unjust gain, wise and understanding. Moreover, Scripture says [that Moses chose them] out of all Israel,108Further, Verse 25. which means [that they were] the preferred of all Israel, being the ones who have all of these qualities. Since Scripture states that he chose them out of all Israel,108Further, Verse 25. it is already stating that they were chosen in preference to all, for it is known that the better ones in Israel possess all good qualities. Jethro, however, not being familiar with them, found it necessary to explain in detail [that they be G-d-fearing, men of truth, etc.]
Some scholars109Ibn Ezra here. Also, R’dak in Sefer Hashorashim, on the root chayil. explain anshei chayil as men of physical strength and zeal, such as have ability to stand in the king’s palace.110Daniel 1:4. Similarly, eisheth chayil107Proverbs 31:10. is a woman of strength and industry in the work of the home, as Scripture explains there in that section.111Proverbs 31:10-31. Likewise, Make them wander to and fro ‘b’cheilcha,’112Psalms 59:12. which means “by Thy power.” Also, Neither doth it, [i.e., the horse], afford escape by its great ‘cheilo,’113Ibid., 33:17. [which means “by its great strength”]. The word [chayil] is associated with the Aramaic, as is evidenced by the [Hebrew] expression, ‘yesh l’eil yadi’ (It is in the power of my hand),114Genesis 31:29. which is rendered in the Targum: “there is cheila in my hand.” And further on it says, And Moses chose men of ‘chayil’ out of all Israel,108Further, Verse 25. which means the preferred ones of the entire nation and all qualities are included, as I have explained.