15:2 And I saw what looked like a sea of glass glowing with fire and, standing beside the sea, those who had been victorious over the beast and its image and over the number of its name. They held harps given them by God.
And I saw what looked like
John continues on looking (Revelation 4:1). He is aware of what is going on. Seeing, observing, being alert is not optional for a believer. It is required:
a SEA OF GLASS glowing with fire and,
The SEA of GLASS is symbolic of the victorious Christ upon whom we can STAND. The fire denotes pending judgment (Hebrews 12:18-29).
Glass is formed by heating up silicates, and this SEA OF GLASS apparently is getting hotter and hotter. Compare this SEA OF GLASS with the one around the throne (Revelation 4:6). They probably are the same but this one reflects the 7 pending bowls of judgment. Hence mixed with FIRE.
standing beside the sea, those who had been VICTORIOUS over the BEAST and its IMAGE and over the NUMBER of its name.
Each of the seven churches had blessings for the persons who were VICTORIOUS (Revelation 2:7, 2:11, 2:17, 2:26, 3:5, 3:12, and 3:21). However, these VICTORIOUS ones are not those from the seven churches. Rather they are the ones who persevered through the beast's deception (Revelation 13:10 and 14:12). They did NOT take the NUMBER (Revelation 13:18).
They held HARPS given them by God.
At the beginning of the seventh trumpet, the people bowed their heads in complete obedience and humble worship (Revelation 11:16). These saints stood tall as witnesses of God’s final judgments. These judgments were for them. They stood in awe of God, they had made the right choice, God was so POWERFUL. They may have known this all along, but the impact of their choice must have been overwhelming at this moment.
Look how Daniel sees this moment (Daniel 12:1-3-4).
The HARP appears to be "the God instrument" (Psalm 33:1-2-3 and Revelation 5:8). The devil knows this and apparently tries to reproduce the same sound/music in Babylon (Revelation 18:22). However, I have a feeling the beast/devil has no idea how to play the HARPs like these STANDING here do!