The distinction of the Elders clearly brought out the description of the New Jerusalem, where the 12 Foundation Stones are named after the Twelve Apostles and the 12 Gates after the Twelve Tribes of Israel in Revelation 21:10-14.

The Elders are representative of both the
Old and New Testament Saints,
       and the Old Testament Saints are represented by the Twelve Tribes of Israel
       and the New Testament Saints are represented by the Twelve Apostles,
       Together they make up the 24 Elders.

The "Four and Twenty Elders" are representative of the redeemed human race.

         Twenty-four is the number of the Priests
given in 1 Chronicles 24:1-19.

    When David distributed the Priests, he found there were 24 Heads of the Priestly families and these 24 heads he made representatives of the whole priesthood.

The time when the right of Judgment is handed onto the Elders [Saints] is given by John as the binding of Satan, and just before the Millennium.

                     Revelation 20:4
"I saw Thrones, and they [the First Resurrection Saints - Elders] sat upon them, and Judgment was given unto them."

It is clear that the Elders round the Throne of God will be given the right to judge.

       Paul wrote to the Corinthians, "Do ye not know that the Saints shall judge the world. . . .Know ye not that we shall judge angels."; the fallen angels.   1 Corinthians 6:2-3

It's clear that the time has not come yet for the Elders to reign, because they are engaged in Priestly duties, having Golden Vials full of odors, which are the prayers of the Saints in their hands Revelation 5:8.

      These Saints are not the saints of the church.
They are the Jewish Saints on earth during the Tribulation Period, whose prayers are written in the Psalms.

While the Elders sit on Thrones and wear Crowns, they are not dressed in royal robes but in white raiments, the garments of a Priest.

          They are the members of a royal priesthood.
           1 Peter 2:9.

"And they sung a New Song, saying, Thou are worthy to take the Book, and to open the Seals thereof, for thou wast slain, and hast redeemed us to God by thy blood, out of every kindred, and tongue, and people, and nation; and hast made us unto our God Kings and Priests; and we shall reign on the earth."
Revelation 5:9-10

       This couldn't be said of angels or any other created heavenly beings.
        They haven't been redeemed by the Blood of the Lamb, nor are they to be Kings and Priests on the earth.

There are five crowns that the Elders could receive.

         1) The Incorruptible Crown
              1 Corinthians 9:25-27
         2) The Crown of Life
              Revelation 2:10
         3) The Crown of Glory
              1 Peter 5:2-4
         4) The Crown of Righteousness
              2 Timothy 4:8
         5) The Crown of Rejoicing
              1 Thessalonians 2:19-20

Daniel's view of the Judgment Seat of Christ.

        While the Thrones were placed (ready for those who should be found worthy to occupy them) they were not yet occupied.
                   Their occupancy had to wait for the outcome of the judgment.

Now as the Thrones that John saw were occupied by crowned Elders. Those Elders must have passed the fiery test of the Judgment of Reward and recieved their crowns.
1 Corinthians 3:11-15
2 Corinthians 5:10

The Elders round about the Throne must be representatives of the Old and New Testament Saints, that have been redeemed by the blood of Christ.

          They are seated on Thrones not ordinary seats, and remind us of  Daniel's Vision of the Judgment in Daniel 7:9-10. . .
"I beheld till the thrones were cast down, and the Ancient of days did sit, whose garment was white as snow, and the hair of his head like the pure wool: his throne was like the fiery flame, and his wheels as burning fire.
A fiery stream issued and came forth from before him: thousand thousands ministered unto him, and ten thousand times ten thousand stood before him: the judgment was set, and the books were opened."

The 'Elders' round about the Throne are not heavenly or unfallen beings like the angels or 'living creatures' that surround the Throne.

           They are the representatives of the redeemed.

The name Elder is never given to angels, neither do angels have crowns and sit on thrones.

           Only the redeemed men are promised Thrones and Crowns.

Matthew 19:28,   Revelation 2:10,  
Revelation 3:21,  Revelation 20:4, 
1 Peter 5:2-4,       2 Timothy 4:8

"And round about the Throne were Four and Twenty seats and upon the Seats I saw Four and Twenty Elders sitting clothed in white raiment; and they had on their heads Crowns of Gold."
Revelation 4:4 

A knowledge of the Tabernacle and its various parts and vessels of service, helps to understand John's vision of the 'Heavenly Tabernacle.'

                  Just like John, Paul was caught up into Heaven, and saw the 'Heavenly Tabernacle' in his letter to the Hebrews.

The 'Glassy Sea' is similar to the 'Brazen Sea' that stood before Solomon's Temple (1 Kings 7:23-45, and was in front of the Ark of the Covenant, the 'Mercy Seat' which was the earthly Throne of God in the Old Testament times.

                 The earthly Tabernacle set up by Moses with all its vessels and instruments of service and types of worship, was patterned after the 'Heavenly Tabernacle' (Hebrews 9:23).

Before the Throne was a "Sea of Glass".

This Sea of Glass was unoccupied, but later is seen mixed with fire (Revelation 15:2-3, and occupied by martyrs of the Tribulation Period who get the victory over the Beast, and who have harps, and sing the Song of Moses and the Lamb.

The 'Throne' was not the 'Throne of Grace' because lightnings and thunderings and voices, that remind us of Mount Sinai came out of it and proclaimed it to be the Throne of Judgment.

If the Rainbow did not encircle the Throne as a "Halo", it might be its reflection in the "Sea of Glass" that makes it appear to John to be round.

The Circular Emerald Rainbow about the Throne of God signifies that God is a Covenant keeping God.

       His promises as to this earth shall be fulfilled.

              Even though He's about to bring great judgments on it, He will not destroy it.
             
                       It shall safely pass through those judgments.
                                
  He will redeem it and bless it.