^5:8And when he had taken it, the four living creatures and the twenty-four elders fell down before the Lamb. Each one had a harp and they were holding golden bowls full of incense, which are the prayers of God’s people.

And when he had taken it, the four living creatures and the twenty-four elders

The first hymn is sung by these 28 .... later hymns are sung by all creation.

fell down before the Lamb. Each one had

This shows equivalence between the LAMB and diety. The 24 elders representing redeemed saints along with the 4 mightest heavenly creatures/angels give due homage.

The inheritance is about to be fulfilled. This suggests the 28 may have had some idea of the awesome contents of the book and seals.

a HARP and

God loves beautiful music. It was part of temple worship, Ezra 3:10-11. The harps are part of the music before the Lamb on Mount Zion, Revelation 14:2. The victorious ones in Revelation 15:2 are holding harps of God.

they were holding golden bowls full of incense, which are the prayers of God’s people.

We see these prayers of the saints again at the breaking of the seventh seal and at the preparation for the blowing of the seven trumpets, Revelation 8:3-4. These prayers may also be the "avengence prayers" of the martyrs, Revelation 6:10.