like a jasper
Jasper describes the light of, foundation, and walls of the holy Jerusalem (Rev. Rev. 21:11+, Rev. 21:18-20+). It was the last of the twelve stones representing the twelve tribes of Israel which were mounted in the breastplate of the high priest (Ex. Ex. 28:20; Ex. 39:13). When Satan was in the Garden of God, his covering included precious stones like jasper (Eze. Eze. 28:13-14). Modern ignorance of ancient terminology makes precise identification of the stones quite tentative (Morris). Probably the equation of iaspidi (jasper stone) to the modern jasper which is dull and opaque (Alford) is wrong because the modern stone is hardly considered costly as the text implies.1 From Rev. Rev. 21:11+, where it is called most precious, which the jasper was not, Ebrard infers it was a diamond.2
like a sardius stone
The sardius, better known in our day as the carnelian, is red. Hengstenberg quotes ancient authorities who call it blood-colored and takes it to describe the righteous wrath of God, the color of the fire of divine anger.3 This stone is also mentioned as part of Satans covering in the Garden of God (Eze. Eze. 28:13). It is the sixth foundation stone of the holy Jerusalem (Rev. Rev. 21:19+) and the first of the twelve stones representing the twelve tribes of Israel in the breastplate of the high priest (Ex. Ex. 28:17; Ex. 39:10). The inclusion of both the first stone, sardius, and last stone, jasper from the breastplate denote the idea of all Israel, first and last, beginning and end, or alpha and omega (Rev. Rev. 1:8+, Rev. 1:17+; Rev. 2:8+).
The jasper and the sardine stone are the first and last of these twelve stones [representing the tribes of Israel]. The jasper represented Reuben, the first of the tribes, since Reuben was the firstborn of Jacob. The sardine stone represented Benjamin, the youngest of the twelve sons of Jacob. In other words, the two stones represented the first and the last and therefore may be regarded as including all the other stones in between, that is, the whole of the covenanted people.4Most see the references to precious stones here (and in Eze. Eze. 28:1) as a description of brilliant colored lights which radiate from God and His throne (Eze. Eze. 1:26-28): We need not find symbolism in each element of the vision; it is enough to allow the archetypical imagery to create the impression of transcendent glory.5
a rainbow around the throne
The brilliant light emanating from the throne resembled a rainbow of emerald hues. The rainbow was given as a sign following Noahs flood to remind God of His covenant never again to destroy all flesh with a flood (Gen. Gen. 9:13-16; Isa. Isa. 54:9-10). Ezekiel saw this same rainbow as the brightness around the throne (Eze. Eze. 1:28). The world that was previously perished in the flood. In the chapters to follow, the judgment will be by fire (2Pe. 2Pe. 3:5-7).
As the rainbow was first reflected on the waters of the worlds ruin, and continues to be seen only when a cloud is brought over the earth, so another deluge, namely, of fire, shall precede the new heavens and earth: the Lord, as here, on His throne, whence (Rev. Rev. 4:5+) proceed lightnings and thunderings, shall issue the commission to rid the earth of its oppressors.6The rainbow is around the throne implying a full circle like a halo.7 A rainbow adorns the head of the mighty angel whose cry precedes the seven thunders (Rev. Rev. 10:1-3+).
like an emerald
The color of the third stone of the high priests breastplate (Ex. Ex. 28:17; Ex. 39:10) and also associated with Satans covering in the Garden of God (Eze. Eze. 28:13). The stone of the fourth foundation of the holy Jerusalem (Rev. Rev. 21:19+).8
2 A. R. Fausset, The Revelation of St. John the Divine, in Robert Jamieson, A. R. Fausset, and David Brown, A Commentary, Critical and Explanatory, on the Old and New Testaments (Oak Harbor, WA: Logos Research Systems, Inc., 1997, 1877), Rev. 4:2.
8 Mounce observes: Ex. 28:17-21 lists the twelve stones, each inscribed and representing a tribe in Israel. Note that the jasper and the carnelian (sardius) are the last and the first (Benjamin and Reuben; cf. Gen. Gen. 49:3-27). On this basis the emerald (no. 4) would stand for the tribe of Judah.Robert H. Mounce, The Book of Revelation (Grand Rapids, MI: William B. Eerdmans Publishing Co., 1977), 134. But in the list of stones given by Exodus Ex. 28:17, the emerald is listed as the third stonethe last in the first row of threeand would represent the tribe of Levi, not Judah.