The scriptures read are Ezekiel 25-26, Psalm 81 and Revelation 4.
Ezekiel 25-26. Ezekiel is commanded to prophesy against Ammon, Moab, Edom, the Philistines and the city of Tyre for their mean-spirited and vengeful behavior towards Judah. Mind you, what happened to Judah was punishment from God but no one is to gloat over another's misfortune.
Psalm 81. A joyful rendition of the first 4 verses of this psalm.
Revelation 4. This is where Revelation turns from a letter into an apocalypse. The main difference between apocalyptic literature and prophesy is that the prophet is hoping for a response of repentance. In apocalyptic writings, it's too late. God is shutting down the evil in the world. All second chances and do-overs are done with. God is lifting the curtain on the cosmic battle that underlies the struggles of God's people.
John is ushered through a door from our reality into God's heavenly court. You will see a lot of symbols reminiscent of the tabernacle in the desert and Solomon's temple. John is seeing the heavenly temple of which the earthly one was a pale imitation. And Revelation is structured like the Jewish order of worship in the Second Temple era. (Thanks to the Baker Illustrated Bible Commentary for that insight.) It started with the lighting of the menorah in chapter 1. Here we enter the Holy of Holies when God is enthroned on the cherubim. Also there is singing.
The 24 thrones encircling God's throne are occupied by 24 elders in priestly robes and crowns, making them a royal priesthood. They are evidently representatives of Israel's 12 tribes plus the 12 apostles. The 4 creatures around the throne resemble the ones Ezekiel saw, except these are 4 creatures with one face apiece. The lion is the king of wild beasts, the ox the strongest domestic beast, the eagle the swiftest of the birds and the human the wisest of God's creatures. They still are covered with eyes. And they have 6 wings each as in Isaiah's vision.
The 7 spirits of God probably refers to Isaiah 11:2 and the sevenfold gifts of the Spirit.
The whole scene is one of worship going on. This will continue throughout the book, sometimes fading into the background of the battle to redeem the world.