In the book of Revelation, why did Jesus have to die?

This article discusses the significance of Christ’s death as explained by Revelation’s vision of the sealed book. Jesus receives a book that is sealed up with seven seals (Rev 5:7, 1). Before His death, nobody was able to open the book (Rev 5:3) but, after He appeared as a slain lamb, Jesus Christ was declared “worthy” to break the seals (Rev 5:5, 9). So, the purpose of this article is to explain why He was not “worthy” to break the seals before His death and how did His death make Him “worthy?”

They overcame Satan by the word of their testimony. Revelation 12:11

Revelation 12:7-10 describes the victory which Michael and his angels gained over Satan in the war in heaven. But then verse 11 describes the victory of “our brethren” over Satan. The first question in this article is whether these refer to the same victory. The second question is why “our brethren” required “the word of their testimony” to overcome Satan. Why is the blood of the Lamb not sufficient?