The prophetic part of the Book of Revelation--unfolding the history of the Church of God, from the days of the apostles till the end of time, is introduced by a vision presenting this covenant sign--"A throne was set in heaven, and one sat on the throne. And he that sat was to look upon like a jasper and a sardine stone: and there was a rainbow round about the throne, in sight like unto an emerald."[679] To the whole period, therefore, of the Church's later history, that sign was to apply. The "four living creatures"--emblematical of the ministers of the gospel, who are also presented in that vision, by this are encouraged to exclaim, "Holy, holy, holy, Lord God Almighty, which was, and is, and is to come;" and by this are they and the four and twenty elders, as a people in covenant with God, led to adore the Lamb, saying, "Thou art worthy to take the book, and to open the seals thereof: for thou wast slain, and hast redeemed us to God by thy blood, out of every kindred, and tongue, and people, and nation;" and to seek to be enabled, as a race wholly devoted to God, truly to say, "Thou hast made us unto our God kings and priests: and we shall reign on the earth."[680] And, finally, before the witnesses for Jesus, ordained to witness a good confession, and in opposition to ignorance and sin in the world, to abide by, yea even to renew, their confession and wonted vows, made by all the solemnity of an oath, the same sign is presented. The promise is made, "And I will give power unto my two witnesses, and they shall prophesy a thousand two hundred and threescore days, clothed in sackcloth."[681] The work committed to these witnesses was arduous. Nor was the finishing of their testimony, in the eyes of the world, enviable. But manifestly great was to be their gracious reward, when they should ascend up to heaven in a cloud, and their enemies behold them. The duty to which they were called, and their high enjoyments to follow, the little book which John was commanded to eat, contained. It appeared open in the hand of that mighty angel--the angel Jehovah--come down from heaven, whose face was as it were the sun, and his feet as pillars of fire. To assure his servants of the stability of his covenant, through which is dispensed his all-sufficient grace, and to prompt them faithfully to perform their high duties, in vision he was seen clothed with a cloud, and with a rainbow upon his head.[682]