Charles Spurgeon Commentary Deuteronomy 33:7-9

"And this is [the blessing] of Judah: and he said, Hear, Jehovah, the voice of Judah, And bring him in unto his people. With his hands he contended for himself; And thou shalt be a help against his adversaries. And of Levi he said, Thy Thummim and thy Urim are with thy godly one, Whom thou didst prove at Massah, With whom thou didst strive at the waters of Meribah; Who said of his father, and of his mother, I have not seen him; Neither did he acknowledge his brethren, Nor knew he his own children: For they have observed thy word, And keep thy covenant." — Deuteronomy 33:7-9 (ASV)

Judah was the royal tribe—it had much to do with warfare. Lord give him power in prayer! This is the distinctive benediction for those who have to lead the way in the battles of God.

In the service of God, Levi was impartial; he did not wink at sin in his dearest relatives. You remember how they took the sword, and went through the camp, and killed their own brothers when they found them guilty of idolatry, and because of this faithfulness we read, They shall teach Jacob thy judgments, and Israel thy law. Above all things, a teacher of the truth of God must be fearless and impartial in the delivery of God's Word; then God will bless him, and it shall be said of such, They shall teach Jacob, etc.