The events described in Revelation 6:1–17 follow in uninterrupted sequence on what is recorded in Revelation 5:1–14. As John was witnessing the various creatures of God’s creation worshipping the Lamb (Revelation 5:13), he saw the Lamb move into action and begin to open the seals of the scroll.
1 Now I watched when the Lamb opened one of the seven seals, and I heard one of the four living creatures say with a voice like thunder, “Come!”