When He had taken the scroll, the four living creatures and the twenty-four elders fell down before the Lamb, each one holding a harp and golden bowls full of incense, which are the prayers of the saints.
Revelation 5:8, NASB
Why did they have the prayers of the saints?
The elders are there as the symbolic leaders and representatives of the saints. The relevant O.T. parallel is Exodus ch24 vv9-11. On that occasion, Moses and Aaron, Nadab and Abihu "and seventy of the elders of Israel" went up the mountain to see "The God of Israel". What they saw, of course, was an image accommodated to their understanding, which is the only way that men can "see God". For "no man has ever seen God", in the true sense (John ch1 v18). An important detail of this image is that "there was under his feet as it were a pavement of sapphire stone, like the very heaven for clearness" (v10, RSV). This detail is shared by the mobile-throne vision of Ezekiel ("There was the likeness of a firmament, shining like crystal"- Ezekiel ch1 v22). It is also shared with the Revelation ch4 scene ("before the throne there is as it were a sea of glass like crystal" v6). These are three scenes of a similar type.
On that basis, I maintain that the elders in Revelation ch4 have the same function as the elders of Exodus ch24. They are the delegated representatives of God's people, the saints, and as such have been symbolically "commissioned" to present these prayers to God. N.B. They are not acting as mediators. They are the plaintiffs themselves, presenting their own petition direct to God. A mediator would be a third party, coming "in the middle" between the plaintiff and God.
As for the living creatures, I suggest that they are on the scene partly as the representatives of living things in general, since the man, the lion, the ox, and the eagle are figures of what might be called leading species of the world as known in the Bible. Their participation makes the point that creation itself "waits with eager longing for the revealing of the sons of God" (Romans ch8 v19)
Why indeed? An answer will help us understand the overall text of Revelation. This is a good thing to ask when reading the Bible.
We learn all we need to learn from Book of Revelation itself. We don't know the full background, but the answers we need are there.
Let's review who these elders are, and the word "elder" itself.
They are first mentioned in 4:4...
Revelation 4:4 (boldface added)
(NASB)
Around the throne were twenty-four thrones; and upon the thrones I saw twenty-four elders sitting, clothed in white garments, and golden crowns on their heads.
(SBLGNT)
καὶ κυκλόθεν τοῦ θρόνου θρόνοι εἴκοσι τέσσαρες, καὶ ἐπὶ τοὺς θρόνους εἴκοσι τέσσαρας πρεσβυτέρους καθημένους περιβεβλημένους ἐν ἱματίοις λευκοῖς, καὶ ἐπὶ τὰς κεφαλὰς αὐτῶν στεφάνους χρυσοῦς.
The word "elder" comes from the adjective πρεσβύτερος (presbuteros, Strong's 4245).
Strong's:
Usage: elder, usually used as subst.; an elder, a member of the Sanhedrin, an elder of a Christian assembly.
We don't have any further definition of their function from the passage about what this word "elder" would have meant. The strongest thing we learn is that, being used to describe a member of the Sanhedrin, they were likely a governing body. The Sanhedrin did have legislative and legal powers, which was why Pontius Pilate would have had trouble dealing the Jewish leaders as they were a semi- or at least quasi-legal force to be reckoned with.
From 4:4, we also learn that they sit on thrones that are around "The Throne", they are clothed in white, and they wear crowns. These words mean basically the same thing in English and Greek, but here are some references for deeper study...
"throne" - θρόνος (thronos, 2362)
"white" - λευκός (leukos, 3022) or "bright"
"crown" - στέφανος (stephanos, 4735) or "wreath" or other honorary adornment for the head
Except the insight that "elder" was also used for voting members of the Sanhedrin, the Greek words basically mean the same thing in English.
This almost looks like a version of the Roman Senate, but instead of being seated in arrangement around Caesar or a speaker's podium, they are seated around God Himself on His Throne, and they are referred to by names reserved for religious-government legislative bodies, not purely government legislative bodies. So, they are both government and led by God Himself.
In 4:10, they cast down their crowns, verifying that they are seated under the authority of God on the Throne.
Revelation 4:10 (NASB) (emphasis added)
the twenty-four elders will fall down before Him who sits on the throne, and will worship Him who lives forever and ever, and will cast their crowns before the throne, saying,
Incense appears elsewhere in Revelation...
The "incense" from 5:8 is from θυμίαμα (thumiama, Strong's 2368), which also has a reference to "burning" or "fragrant stuff for burning, incense" (Vine's). Again, the English meaning is basically the same as the Greek.
From 5:8, we do know that this incense is the "prayers of the saints".
Incense also appears in Chapter 8...
Revelation 8:3-5 (NASB)
3 Another angel came and stood at the altar, holding a golden censer; and much incense was given to him, so that he might add it to the prayers of all the saints on the golden altar which was before the throne. 4 And the smoke of the incense, with the prayers of the saints, went up before God out of the angel’s hand. 5 Then the angel took the censer and filled it with the fire of the altar, and threw it to the earth; and there followed peals of thunder and sounds and flashes of lightning and an earthquake.
In v3, we learn that incense on the golden altar was the prayers of all the saints—Greek trying to explain that all prayer/incense goes to the altar. In v4, the prayers rise up before the Lord in the form of incense. In v6, we see that these prayers make quite a big difference on earth.
Moreover, looking back at v3, we see that the business of the throne room in Heaven was interrupted for this matter of incense and prayers from the saints to do important work on earth. The three verses in 8:3-5 are an interruption of the events that began in ch4.
So, we can conclude that prayer/incense is important around the throne of God and is important enough to interrupt other business in the throne room.
We could even argue that, since each elder has a bowl dedicated to this prayer/incense, and that the altar before the throne itself is the final destination of all this prayer/incense, that prayer itself is one of the primary functions of the throne room—and delivering or handling collected prayers requests before the the Lord is a primary function of these elders. They also have harps, and there is worship in the throne room, so prayer is not the only function of the throne room, but one of the most important functions.
This is consistent with how many kings and even government leaders operate today, who take time to hear out the petitions and requests of the people, in any form of government.
The altar seems to be a central collection place for prayer/incense. We learn more about what happens there in ch6 when the fifth seal is opened.
Revelation 6:9-11 (NASB)
9 When the Lamb broke the fifth seal, I saw underneath the altar the souls of those who had been slain because of the word of God, and because of the testimony which they had maintained; 10 and they cried out with a loud voice, saying, “How long, O Lord, holy and true, will You refrain from judging and avenging our blood on those who dwell on the earth?” 11 And there was given to each of them a white robe; and they were told that they should rest for a little while longer, until the number of their fellow servants and their brethren who were to be killed even as they had been, would be completed also.
Apparently, Christian martyrs are under the altar, making their own prayer/incense petition to God directly. They aren't making petitions through a legislative body like a Senate or Sanhedrin, but directly. This is a contrast.
These elders are public servants hearing out the needs of the people as the servant leaders Jesus described. Being leaders under God and the Lamb, these leaders must have met Jesus's qualifications for leadership...
Matthew 20:26 (NASB)
It is not this way among you, but whoever wishes to become great among you shall be your servant,
So, what is the bowl in the hands of an elder for? To deliver the requests of the people through God's government administration.
Rev 5:8 appears to be an allusion to Ps 141:2 which says this:
May my prayer be set before You like incense, my uplifted hands like the evening offering.
Thus, the prayers of the righteous have always been represented by the metaphor of incense.
Thus, in Rev 5:8, all heaven is interested in the prayers of the saints; not that God needs to be reminded about what the saints are saying; as with all else in Revelation, it is a metaphor for showing the participation of all heaven's personnel in the process of God's salvation.
Ellicott says this:
It is not the Church alone which is interested in the revelation which will throw light on life’s mysteries and the delay of the kingdom: the whole creation groaneth, waiting for the reign of righteousness; and therefore the four living beings, who represent creation, join with the elders, who represent the Church, in the adoration of the Lamb who holds the secret of life’s meaning in His hand. The vials (which seem to be censers, as they hold the incense) and the harps, it is perhaps more natural to suppose, were in the hands of the four-and-twenty elders, and not of the living creatures. Here, then, we have the praises (represented by the harps), and the prayers (represented by the censers) of the world-wide and age-long Church of Christ.
Indeed, the 24 elders and the four living creatures then use the prayers of the saints (represented by the incense) as a further excuse to praise God and the Lamb as recorded in Rev 5:9, 10.
Appendix
Note that whatever the 24 elders are doing with the prayers of the saints, it is NOT acting as a mediator because that is the sole function of Christ Jesus as per:
1 Tim 2:5 - "For there is one God and one mediator between God and mankind, the man Christ Jesus"
