The beast … it was, and now is no more, but is about to come up: When Domitian was emperor, from AD 81 to 96, he was as evil as Nero. Both fiercely persecuted the church. Many believed Domitian embodied Nero’s spirit or was Nero himself. This is similar to how people thought John the Baptist embodied Elijah’s spirit (see Malachi 4:5; Matthew 11:14; Luke 1:17; John 1:21).
you saw: The past tense shows the angel explained this after John’s vision.
it was, and now is no more: This contrasts with God, who is and was and is to come (Revelation 1:4, 8).
the Abyss: See study note on Revelation 9:1–12.
Unlike God’s people, the people of this world are not in the Book of Life (see Revelation 20:11–15). They will be amazed by the beast’s apparent resurrection (see study note on Revelation 17:10–11; see also 13:13–17).