‘And another angel came and stood over the altar, having a golden censer, and much incense was given to him in order that he should offer it with the prayers of all God's people (‘all the set apart ones' or ‘all the saints') on the golden altar which is before the throne. And the smoke of the incense with the prayers of the God's people (the set apart ones - the saints) went up before God out of the angel's hand. And the angel takes the censer and he filled it with the fire of the altar and cast it on the earth. And there followed thunders, and voices, and lightnings, and an earthquake.'
The angel, who is not identified, stands at the heavenly altar of incense ready to make his offering before God. He is one of many angels with specific tasks to perform. Who he is it is idle to speculate. He is anonymous. He is only important because of the task he performs. The golden altar of incense is before the throne, just as the altar of incense in the Tabernacle was before the veil behind which was the mercy seat, the throne of God. The incense is thus offered directly to God.
The angel is given incense which will amplify the prayers of God's people as they are offered to God. Such effective prayer is necessary in view of what we learn about the trumpets and the seals. In Revelation 5:8 the twenty four elders who act for the church of Christ hold golden bowls full of incense which are the prayers of the saints. This angel's task is to enhance those prayers with further prayers, and Scripture elsewhere tells us the divine source of those prayers in the Great Intercessor (Romans 8:26; Romans 8:34; Hebrews 7:25).
The ‘much incense' given to the angel is to be seen as comprising the intercession of Christ, ‘who ever lives to make intercession for us' (Romans 8:34), and of the Spirit Who ‘makes intercession for us with groanings which cannot be uttered' (Romans 8:26-27), for what else could boost the prayers of God's people? If any particular prayers are specifically in John's mind they are probably those of the souls under the altar in Revelation 6:9-10, for these are about to be answered. (This is all of course picture language. It is not recommending the use of incense in churches, nor saying that there are priests in Heaven, it is using Old Testament ceremonies to apply New Testament truths. Prayer, praise and thanksgiving have replaced incense and are actually what is offered).
In Revelation we are constantly reminded that the people of God are praying (Revelation 5:8; Revelation 6:10). They pray that His name may be glorified, that His kingly rule may come and that His will may be done (Matthew 6:10). And Revelation is the fulfilment of those prayers, although possibly not in the way that they expected. As God's people pray for deliverance so does God continue His acts of judgment which partly bring about those prayers.
Having offered up the incense by burning it in the fire on the altar, thus effectively assisting God's people, the angel fills the censer with the fire from the altar, which has been used to offer up the prayers of God's people, and casts it on the earth, thus applying their prayers directly and ensuring their fulfilment. What will now happen on earth is God's response to the prayers of God's people. He is about to carry out His righteous judgments. In Ezekiel a similar action is performed by the man clothed with linen who had sealed God's people to secure their protection (Ezekiel 10:2). In that case it would result in the carrying our of God's righteous judgments in the devastation of the city of Jerusalem.
We are not to see these ideas as literal. (It is described in earthly terms. There is no need or place for an altar in Heaven for it is essentially spiritual). They are intended to assure the people of God that God is constantly aware of their prayers and to assure them that the intercession of Christ and the Holy Spirit is effective on their behalf. They also assure them of the interest of heavenly beings in their needs and problems. The prayers directly in mind are the prayers for assistance in the face of trial, and longings for the fulfilment of God's purposes. It does not have in mind our prayers for the sorting out of our personal day to day lives, although it does include our prayers for protection from evil.
If we were to take Revelation 15:8 literally it is an awesome thought that the above may be the last ‘priestly' act carried out by angels until the resurrection. The prayers of God's people for the working out of God's purposes have been heard, those prayers have been applied on earth, and all that follows in the future will be the working out of the answer to those prayers.
‘There followed thunders, and lightnings, and voices and an earthquake'. As mentioned previously on Revelation 4:5 the first three of these indicate something of the glory and mystery of God. They declare that something very important is about to happen. To these are added the earthquake to draw attention to the fact that God's judgments are in process and that there will be earth shaking events. Earthquakes are depicted in Revelation as indicators and reminders of the judgment of God, and as part of those judgments.