Here we have a very brief pause between the announcements of the three angels (verses 6, 8, and 9) and the harvesting of the earth and the final judgments, 7 bowls.
And I heard a voice from heaven, saying,
Not clear whether this is an angel's voice or Christ's voice. It is clear that it is NOT an earthly voice.
"Write, Blessed are the DEAD who DIE IN THE LORD from now on!
These are those who during the tribulation period (Matthew 24:21) refuse to take the mark of the beast (verse 11).
This also is the second beatitude of Revelation. See Revelation 1:3 for a discussion of these beatitudes.
The expression 'from now on' indicates that this is a very specific time during the tribulation. This fits with the precise timings in the rest of the Revelation.
Yes," says the Spirit, "that they may REST from their LABORS, for their DEEDS follow with them."
Other than in Revelation 22:17, this is the only place where the SPIRIT speaks directly. It is as though, the SPIRIT is being released from His commission to be the Comforter, John 14:15-24. Then as now, He usually is in the background working through the believers.
Also implied here is that even under much distress, believers WILL and DO WORK DILIGENTLY for the Lord. This continues right until DEATH. Then, oh how sweet is that FOREVER REST!