Render "For the leading of the leaders in Israel (the princes), for the willingness of the people (to follow them) bless ye the Lord." See Deuteronomy 32:42 note, and compare Judges 5:9 and Judges 5:13, where the nobles and the people are again contrasted.

For the avenging of Israel - See the notes, etc., at the end of the chapter, Judges 5:28 (note).

Praise ye the LORD for the avenging of Israel, when the (a) people willingly offered themselves.
(a) That is, the two tribes of Zebulun and Naphtali.

Praise ye the Lord for the avenging of Israel,.... The injuries done to Israel by any of their enemies, and particularly what wrongs had been done them by Jabin, king of Canaan, for twenty years past; though some understand it of the vengeance God took on Israel for their sins; and though praise is not given directly for that, yet inasmuch as, when that was the case, there were some whose spirits were stirred up to engage voluntarily in the deliverance of them from the oppression of their enemies, it was matter of praise:
when the people willingly offered themselves: to go and fight for Israel against their enemies, particularly those of the tribes of Zebulun and Naphtali, Judges 5:18; though not excluding others that joined, who could not have been forced to it, had they not freely offered themselves; and which was owing to the secret influence of divine Providence on their hearts, moving and drawing them to this service; and therefore praise was due to the Lord on this account, who works in the hearts of men both to will and to do, as in things spiritual and religious, so in things natural and civil.

The meaning is obscurely seen in our version; it has been better rendered thus, "Praise ye Jehovah; for the free are freed in Israel--the people have willingly offered themselves" [ROBINSON].

2 That the strong in Israel showed themselves strong,
That the people willingly offered themselves,
Praise ye the Lord!
The meaning of פּרע and פּרעות is a subject of dispute. According to the Septuagint rendering, and that of Theodot., ἐν τῷ ἄρξασθαι ἀρχηγοὺς ἐν Ἰσραήλ, many give it the meaning to begin or to lead, and endeavour to establish this meaning from an Arabic word signifying to find one's self at the head of an affair. But this meaning cannot be established in Hebrew. פּרע has no other meaning than to let loose from something, to let a person loose or free (see at Leviticus 10:6); and in the only other passage where פּרעות occurs (Deuteronomy 32:42), it does not refer to a leader, but to the luxuriant growth of the hair as the sign of great strength. Hence in this passage also פּרעות literally means comati, the hairy ones, i.e., those who possessed strength; and פּרע, to manifest or put forth strength. The persons referred to are the champions in the fight, who went before the nation with strength and bravery. The preposition בּ before פּרע indicates the reason for praising God, or rather the object with which the praise of the Lord was connected. וגו בּפרע, literally "in the showing themselves strong." The meaning is, "for the fact that the strong in Israel put forth strength." התנדּב, to prove one's self willing, here to go into the battle of their own free will, without any outward and authoritative command. This introduction transports us in the most striking manner into the time of the judges, when Israel had no king who could summon the nation to war, but everything depended upon the voluntary rising of the strong and the will of the nation at large. The manifestation of this strength and willingness Deborah praises as a gracious gift of the Lord. After this summons to praise the Lord, the first part of the song opens with an appeal to the kings and princes of the earth to hear what Deborah has to proclaim to the praise of God.

The Lord - Give him the praise who hath done the work. The people - Chiefly Zebulun and Naphtali. Offered themselves - When neither Deborah nor Barak had any power to compel them.