New Defender's Study Bible Notes
8:13 heard an angel. No longer can those on earth question the reality of God and His power when they hear and see a mighty angel flying in the sky proclaiming further judgments yet to come. Some manuscripts translate this as “eagle,” which is probably an early corruption of certain texts. If he is an eagle, however, he must be the fourth cherub at God’s throne (Revelation 4:7), with the likeness of a flying eagle.