Julian of Toledo

As is clear to all, Daniel himself gave the name of the very angel in the book of his prophecy, when he learned from the angel those mysteries of the weeks that would take place concerning the birth of Christ.… According to the Gospel, the wonderful name of the very angel was found to have been given again in these times, for the same angel told Zechariah, “I am Gabriel and I stand before God.”

The thousand years refers to when the church of God which, by the diffusion of its faith and works, is spread out as a kingdom of faith from the time of the Incarnation until the time of the coming judgment.