The door mentioned here as being opened in heaven was to the heavenly sanctuary, the throne room of heaven as evidenced by verse 2 and verse 5. The "seven lamps of fire" are the antitype of the seven-branched candlestick that was in the first apartment of the sanctuary. Isaiah 6:1-5; Ezekiel 1; Acts 7:56. Also Exodus 25:31,32,37; 26:35; 27:20.

4:2-4 The special focus of the book of Revelation is Jesus’ work as our High Priest and the events that occur during and after the completion of His ministry. When the work is finished He will put on His kingly garments and return to Earth to claim His people.

Ezekiel 1:26 describes God's throne as having the appearance of a sapphire stone.

The “rainbow” around the throne shows the beauty to be found in holiness; it brings to mind Noah, and the promise God made not to again destroy the earth with a flood. (Genesis 9:13-17) The “rainbow” is God’s pledge that He will honor His promises. It is a mixture of sunshine and rain - just as God's throne is a blend of mercy and justice.

The rainbow round about the throne is an assurance that God is true, that in Him is no variableness, neither shadow of turning. We have sinned against Him, and are undeserving of His favor; yet He Himself has put into our lips that most wonderful of pleas, “Do not abhor us, for Thy name's sake; do not disgrace the throne of Thy glory; remember, break not Thy covenant with us.” Jeremiah 14:21. When we come to him confessing our unworthiness and sin, He has pledged Himself to give heed to our cry. The honor of His throne is staked for the fulfillment of His word unto us. ^i.

The “four and twenty elders” are engaged in worshipping God and assisting in the heavenly sanctuary services. Revelation 5:5, 8-11.

But who are these elders? Where did they come from? Their white robes and the crowns on their heads indicate that they have gained victory over sin - sinners saved by grace. In Chapter 5:9, they themselves declare that they have been "redeemed from the earth" by God's blood "out of every kindred, and tongue, and people, and nation". When Jesus died, the graves were opened and many dead were resurrected and went into Jerusalem and appeared to many. (Matt 27:50-53) This is indicated also in Psalm 68:18 and Ephesians 4:8 where it refers to leading "captivity captive". These resurrected ones were taken to heaven when Jesus went to heaven as firstfruits with Christ. (1 Cor 15:20) These 24 elders seem to be from that company.

A priest had to be chosen from among his brethren. Hebrews 2:17. These men, being priests, were the chosen representatives from every race and nation of the world. When Christ arose from the grave, "many bodies of the saints which slept arose, and came out of the graves." Matthew 27:52, 53. Then "when He ascended on high, He led a multitude of captives." Ephesians 4:8, margin.

It was in this sense that He became "the first-born among many brethren." Romans 8:29. When He was installed as our High Priest, He was anointed with the oil of gladness above his fellows. They were His "brethren" who arose with Him from the grave. They were the antitypical wave-sheaf offering, as it were, and became the antitype of the ceremonial in the Mosaic ritual. Leviticus 23:15.

4:5 The Holy Spirit is represented by the “seven lamps” burning in the heavenly sanctuary. Seven is a figure of completeness or perfection. The Holy Spirit brings light into the lives of God’s people and illuminates the way to salvation. Revelation 5:6 tells us that the seven Spirits of God are the eyes of the Lord, and Zechariah 3:9 and 4:10 tells us that the eyes of the Lord run to and fro in the earth. This is symbolic of God's spirit that works in behalf of men and God's omniscience that sees all things hidden and secret. The Holy Spirit searches constantly throughout the whole world for those whose hearts are perfect toward Him. 2 Chronicles 16:9; Proverbs 15:3

4:6-8 The "sea of glass" here mentioned is also mentioned in Revelation 15:2 as the place where the overcomers stand before God and praise Him who has given them the victory.

The “beasts” or living creatures in this scene are similar to the angel cherubim in Ezekiel’s vision. The shapes of the living creatures were symbolic. (In this same vision Jesus was represented as both a lion and a lamb, symbolizing His power and His gentleness.) Similar imagery is used in Ezekiel chapter 1. There are different opinions about the different qualities of each of the living creatures. In general it is believed that the human face symbolizes reason or Jesus’ humanity; the lion’s face, strength; the ox’s willingness to serve or perseverance; and the eagle’s swiftness to obey or perceptiveness. Like the elders, these living creatures ascribe to God praise for having redeemed them from the earth in Revelation 5:9. They therefore belong to the same company and represent a part of the great multitude, who, as already described, have been led up on high from the captivity to death. Ezekiel chapters 1 and 10 seem to indicate that these creatures may be part of God's moveable throne.

Another idea is suggested for the meaning of the symbolism of the four living creatures by Roy Allan Anderson in his book Unveiling Daniel and the Revelation:

Commentators for centuries have linked these symbols with the four aspects of our Saviour as emphasized particularly in the four Gospels.

Matthew writes on the kingly side of our Lord, emphasizing the King and His kingdom. This is well symbolized by the lion, the majestic king of beasts.

Mark deals largely with the Saviour as a servant of man, the ox symbolizing service. Luke, the physician, reveals His human aspect as the Son of man, hence the face of a man. John emphasizes His diety—Christ the Eternal Word—who created all things. This phase of our Lord is symbolized by the flying eagle.

Though the account of the organization of Israel in the wilderness as given in Numbers 2 does not so state, non-Biblical records indicate that these symbols were used as follows: the section grouped around Judah were under the lion standard; those standing near Ephraim, under the ox; those around Reuben, under the standard of a man; and those around Dan, under the flying eagle.

"They rest not" is a happy unrest as the theme of their constant worship is the holiness of God. They repeat it "day and night" or continually - but it is not a mindless kind of repetition, but an intelligent statement.

We mortals are likely to tire of the repetition of the simple testimony we bear here to the goodness and mercy of God. We are sometimes tempted to say nothing, because we cannot continually say something new. But may we not learn a profitable lesson from the course of these holy beings above, who never grow weary of the ceaseless repetition of these words, "Holy, holy, holy, Lord God Almighty;" and to whom these words never grow old, because their hearts ever glow with a sense of His holiness, goodness and love? Praise does not become to them monotonous, for with every utterance they gain a new view of the attributes of the Almighty. They reach a greater height of comprehension in their vision of His perfections; the horizon expands before them; their hearts enlarge; and the new emotions of adoration draw from them a fresh utterance of their holy salutation, new even to themselves, "Holy, holy, holy, Lord God Almighty! ^ii.

4:9-11 God is worthy of praise and honor because He “created all things.” Satan has attacked God’s status as Creator with the lie of evolution, and he has prompted men to discard the fourth commandment that identifies God as the Creator. “For in six days the Lord made heaven and earth.” Exodus 20:9-11.