Revelation 10

0 witnesses of Christ here, and 2 further echoes from the reading.

Creation by Christ

And sware by him that liveth for ever and ever, who created heaven, and the things that therein are, and the earth, and the things that therein are, and the sea, and the things which are therein, that there should be time no longer: Revelation 10:6

The angel swears by the everlasting Creator. In Revelation this phrase usually points to the Father on the throne, but Latter-day Saints also know that the Father created all things through the Son, and Christ calls Himself 'he that liveth' in Revelation 1:18.

A readingEchoAn echo of Himthe Father or the Son

alludes to John 1:3 — All things were made by the Word.
the same title in Revelation 1:18 — Christ: 'I am he that liveth, and was dead.'

Second Coming

But in the days of the voice of the seventh angel, when he shall begin to sound, the mystery of God should be finished, as he hath declared to his servants the prophets. Revelation 10:7

The seventh trumpet finishes God's work. Joseph Smith's revelation explains that the sounding of these trumpets is the preparing of the way before the time of Christ's coming.

A readingEchoA prophecy of Hima messenger speaking for Him

interpreted by D&C 77:12 — The trumpets are the preparing of the way before the time of His coming.
fulfilled by Revelation 11:15 — When the seventh angel sounds, the kingdoms become the kingdoms of our Lord and of His Christ.