Jamieson, Fausset and Brown on Revelation 5:7

7. The book lay on the open hand of Him that sat on the throne for any to take who was found worthy [Alford]. The Lamb takes it from the Father in token of formal investiture into His universal and everlasting dominion as Son of man. This introductory vision thus presents before us, in summary, the consummation to which all the events in the seals, trumpets, and vials converge, namely, the setting up of Christ's kingdom visibly. Prophecy ever hurries to the grand crisis or end, and dwells on intermediate events only in their typical relation to, and representation of, the end.