Charles Ellicott Commentary Revelation 4:3

"and he that sat [was] to look upon like a jasper stone and a sardius: and [there was] a rainbow round about the throne, like an emerald to look upon." — Revelation 4:3 (ASV)

And he that sat was to look upon like a jasper and a sardine stone.—In determining the significance of these emblems we must be guided partly by the analogy of Bible imagery elsewhere, and partly by our knowledge of precious stones.

The sardian, or sardine, is acknowledged to be a stone of fiery red colour; the emerald, to which the bow around the throne is compared, is almost certainly a bright green; the hue of the jasper is the difficulty. The jasper—the last stone in the high priest’s breastplate, and first of the twelve foundations of the New Jerusalem (Exodus 28:20 and Revelation 21:19)—is described by the best authorities as a dark, opaque green. Such a colour is quite in harmony with the colours of the other stones in the breastplate, and particularly with the foundation stones. These foundation stones seem to be arranged in shades of colour (see Notes on Revelation 21:19 and following). However, the dark opaque green would be a poor combination with the red sardius and the green emerald in the vision of this chapter.

Is there no further light? We have a jasper stone spoken of in Revelation 21:11; Revelation 21:18, with the descriptive phrase, clear as crystal! Does this not point to a stone somewhat different in appearance from that spoken of simply as jasper? Such a clear crystal stone would be the most natural companion to the sardine, and the combination of the sparkling brightness and fiery red fits the union of brightness and flame that appears elsewhere in the Bible (Revelation 11:1; Ezekiel 1:4; Ezekiel 8:2; Daniel 7:9), and is best understood of the holiness and righteousness of God.

The latter half of this verse shows us these surrounded by the emerald-coloured bow, the evident symbol of divine mercy. The allusion to the bow in the cloud (Genesis 9:12–16) is obvious; the bow completely encircled the throne, as mercy encompassing judgment. It was a covenant token, bearing witness to God’s faithfulness in dark times, God’s care for the ark of His Church, and His mercy shining forth after storm.