Adam Clarke

The Lion of the tribe of Juda - Jesus Christ, who sprang from this tribe, as his genealogy proves; see on Mat 1:2 (note), Mat 1:3 (note) and Luk 3:23 (note). There is an allusion here to Gen 49:9, Judah is a lion's whelp; the lion was the emblem of this tribe, and was supposed to have been embroidered on its ensigns. The Root of David - See Isa 11:1. Christ was the root of David as to his Divine nature; he was a branch out of the stem of Jesse as to his human nature. Hath prevailed - By the merit of his incarnation, passion, and death. To open the book - To explain and execute all the purposes and decrees of God, in relation to the government of the world and the Church.