Revelation 10:8

the voice which I heard from heaven
The same voice which instructed John not to write what the seven thunders uttered (Rev. Rev. 10:4+). The divine authority of this voice is seen in its command which countermanded God’s earlier instructions that John was to record what he saw. Here, the divine authority is seen again in that John boldly approaches a mighty angel and tells him to turn over the book.

open in the hand
See commentary on Revelation 10:2.

who stands on the sea and on the earth
See commentary on Revelation 10:2.
Read Revelation 10:8