These are they which came out of great tribulation, and have washed their robes, and made them white in the blood of the Lamb. Revelation 7:14.
(WGD 238.1)
Upon the crystal sea before the throne, that sea of glass as it were mingled with fire,—so resplendent is it with the glory of God,—are gathered the company that have “gotten the victory over the beast, and over his image, and over his mark, and over the number of his name.” With the Lamb upon Mount Zion, “having the harps of God,” they stand, the hundred and forty and four thousand that were redeemed from among men; and there is heard, as the sound of many waters, and as the sound of a great thunder, “the voice of harpers harping with their harps.” ... “These are they which came out of great tribulation;” they have passed through the time of trouble such as never was since there was a nation; they have endured the anguish of the time of Jacob’s trouble; they have stood without an intercessor through the final outpouring of God’s judgments. But they have been delivered, for they have “washed their robes, and made them white in the blood of the Lamb.”—The Great Controversy, 648.
(WGD 238.2)
The most exalted of the redeemed host that stand before the throne of God and the Lamb, clad in white, know the conflict of overcoming, for they have come up through great tribulation. Those who have yielded to circumstances rather than engage in this conflict, will not know how to stand in that day when anguish will be upon every soul, when, though Noah, Job, and Daniel, were in the land, they could save neither son nor daughter, for every one must deliver his soul by his own righteousness.—Testimonies for the Church 5:215.
(WGD 238.3)