As Moses prayed for Judah, so too did he pray for his seed, and especially for David and the royal dynasty of David. He said: "When David, king of Israel, shall be in need, and shall pray to Thee, then, 'Hear, Lord, his voice, and Thou shalt be an help against his adversaries,' 'bring him' then back 'to his people' in peace; and when alone he shall set out into battle against Goliath, 'let his hands be sufficient for him, and Thou shalt be an help against his adversaries.'" Moses at the same time prayed God to stand by the tribe of Judah, whose chief weapon in war was the bow, that their 'hands might be sufficient,' that they might vigorously and with good aim speed the arrow.
Moses's Prayer Shapes the Military Destiny of Judah
Legends of the Jews 7:33