"Behold a throne was set in heaven, and One sat on the throne -Revelation 4:2.
The One whom John saw was God Almighty Himself, in His manifested glory. I say 'in His manifested glory', for the sight of God in His essential glory is something which no man could survive; for St Paul tells us that God 'dwells in the light which no man can approach unto; whom no man hath seen, nor can see' 1 Tim. 6: 16.
In v. 3 John tells us that 'He that sat was to look upon like a jasper and sardine stone.' Gods presence shone with the blinding brilliance of the diamond, denoting His holiness; and glowed like a cornelian, with the concentrated redness of a furnace, depicting His fierce indignation against sin. Hence also 'the lightenings, and thunderings, and voices that proceeded out of ther throne', in v. 5; for 'our God is a consuming fire'. He was on Mount Sinai; He was ,on Mount Calvery. He is today; for He is the same yesterday, and today, and forever.
But thank God, 'there was a rainbow round about the throne, in sight like unto an emerald' v.3. The rainbow was the emblem of the covenant of grace. In this rainbow the soft green of the emerald predominated, perhaps indicating that as the green relieves the eye, which the other colours would have blinded, so the revelation of the covenant mercy of God relieves the mind of the believer, who would otherwise be terrified by the awful sight of God's holiness and justice.
Let us look up to Him in simple trust; and let us fall down before Him, with the cherubim, the four and twenty elders, the myriads of angels, and the whole universe, and let us give Him the love and the adoration and the trust which are His due.