Revelation 4:6

and in front of the throne is what seemed to be a sea of glass, 'resembling crystal, while within the space before the throne and round the throne are four Creatures full of eyes' in front and behind.

Revelation 5:6

Then, within the space between the throne and the four Creatures, and in the midst of the Councillors, I saw, standing, a Lamb, which seemed to have been sacrificed. It had seven horns and seven eyes. (These eyes are the seven Spirits of God, and they are sent into all the world.)

Revelation 15:2

Then I saw what appeared to be a sea of glass mixed with fire; and, standing by this sea of glass, holding the harps of God, I saw those who had come victorious out of the conflict with the Beast and its image and the number that formed its name.

Revelation 7:11

And all the angels were standing round the throne and the Councillors and the four Creatures, and they prostrated themselves on their faces in front of the throne and worshiped God,

Revelation 14:3

They are singing what seems to be a new song, before the throne, and before the four Creatures and the Councillors; and no one was able to learn that song except the hundred and forty-four thousand who had been redeemed from earth.

Revelation 15:7

One of the four Creatures gave the seven angels seven golden bowls, filled with the Wrath of God who lives for ever and ever.

Revelation 19:4

Then the twenty-four Councillors and the Four Creatures prostrated themselves and worshiped God who was seated upon the throne, crying-- 'Amen, Hallelujah!';

Revelation 4:8-9

These four Creatures have each of them six wings, and all round, and within, they are full of eyes; and day and night they never cease to say-- 'Holy, holy, holy is the Lord, our God, the Almighty, who was, and who is, and who shall be.'

Revelation 5:14-1

And the four Creatures said 'Amen,' and the Councillors prostrated themselves and worshiped.

Revelation 7:17

for the Lamb that stands in the space before the throne will be their shepherd, and will lead them to life-giving springs of water; and God will wipe away all tears from their eyes.'

Revelation 21:11

Its brilliance was like that of some very precious stone, like a jasper, transparent as crystal.

Revelation 21:18

The material of the wall of the City was jasper, and the City was built of pure gold, which shone like clear glass.

Revelation 21:21

The twelve gates were made of twelve pearls, each gate of one pearl. The street of the City was of pure gold, transparent as glass.

Revelation 22:1

And the angel showed me 'a river of the Water of Life,' as clear as crystal, issuing from the throne of God and of the Lamb,

Treasury of Scripture Knowledge

Summary

And before the throne there was a sea of glass like unto crystal: and in the midst of the throne, and round about the throne, were four beasts full of eyes before and behind.

Bible References

A sea

Revelation 15:2
Then I saw what appeared to be a sea of glass mixed with fire; and, standing by this sea of glass, holding the harps of God, I saw those who had come victorious out of the conflict with the Beast and its image and the number that formed its name.

Crystal

Revelation 21:11
Its brilliance was like that of some very precious stone, like a jasper, transparent as crystal.
Revelation 22:1
And the angel showed me 'a river of the Water of Life,' as clear as crystal, issuing from the throne of God and of the Lamb,

The midst

Revelation 5:6
Then, within the space between the throne and the four Creatures, and in the midst of the Councillors, I saw, standing, a Lamb, which seemed to have been sacrificed. It had seven horns and seven eyes. (These eyes are the seven Spirits of God, and they are sent into all the world.)
Revelation 7:17
for the Lamb that stands in the space before the throne will be their shepherd, and will lead them to life-giving springs of water; and God will wipe away all tears from their eyes.'

Four beasts

Revelation 4:8
These four Creatures have each of them six wings, and all round, and within, they are full of eyes; and day and night they never cease to say-- 'Holy, holy, holy is the Lord, our God, the Almighty, who was, and who is, and who shall be.'
Revelation 5:6
Then, within the space between the throne and the four Creatures, and in the midst of the Councillors, I saw, standing, a Lamb, which seemed to have been sacrificed. It had seven horns and seven eyes. (These eyes are the seven Spirits of God, and they are sent into all the world.)
Revelation 6:1
Then I saw the Lamb break one of the seven seals, and I heard one of the four Creatures crying with a voice like thunder--'Come.'
Revelation 7:11
And all the angels were standing round the throne and the Councillors and the four Creatures, and they prostrated themselves on their faces in front of the throne and worshiped God,
Revelation 14:3
They are singing what seems to be a new song, before the throne, and before the four Creatures and the Councillors; and no one was able to learn that song except the hundred and forty-four thousand who had been redeemed from earth.
Revelation 15:7
One of the four Creatures gave the seven angels seven golden bowls, filled with the Wrath of God who lives for ever and ever.
Revelation 19:4
Then the twenty-four Councillors and the Four Creatures prostrated themselves and worshiped God who was seated upon the throne, crying-- 'Amen, Hallelujah!';

Full

Revelation 4:8
These four Creatures have each of them six wings, and all round, and within, they are full of eyes; and day and night they never cease to say-- 'Holy, holy, holy is the Lord, our God, the Almighty, who was, and who is, and who shall be.'