5:5 Then one of the leaders said to me, “Stop crying! The Lion from the tribe of Judah, the Root of David, has won the victory. He can open the scroll and the seven seals on it.”
Then one of the leaders said to me,
This is IMPORTANT....it is not an angel talking to John but rather one of the leaders, a redeemed one. Having been redeemed, the leader is able to admonish John to
“Stop crying! The Lion from the tribe of Judah,
the Root of David,
The Jews have long considered that David was the ultimate leader. Thus, it is appropriate that the Root (creator) of David is identified here. Not only the Root but also the Offspring (Revelation 22:16) too.
has won the victory. He can open the scroll and the seven seals on it.”
This is the same "victory" used with the seven churches in chapters 2 and 3. Since Christ is all-knowing, He knew that his assignment when he came to earth was to `overcome' by dying and by coming back to life again. He said as much in John 10:14-18.