Revelation 19:8

for the fine linen is the righteous acts of the saints.
Righteous acts is δικαιώματα [dikaiōmata] : righteous [things]. Her righteous acts are not found on their own. Truly righteous acts are always found in company with and motivated by faith:

But do you want to know, O foolish man, that faith without works is dead? Was not Abraham our father justified by works when he offered Isaac his son on the altar? Do you see that faith was working together with his works, and by works faith was made perfect? And the Scripture was fulfilled which says, “Abraham believed God, and it was accounted to him for righteousness.” And he was called the friend of God. You see then that a man is justified by works, and not by faith only. (Jas. Jas. 2:20-24) [emphasis added]

It must be observed that the “righteousness of the saints” is plural and can not refer to the imparted righteousness of Christ, which is the believer’s portion, but the righteousnesses which have survived examination and have become the basis for reward [1Cor. 1Cor. 3:9-15].⁴

I will greatly rejoice in the LORD, My soul shall be joyful in my God; for He has clothed me with the garments of salvation, He has covered me with the robe of righteousness, as a bridegroom decks himself with ornaments, and as a bride adorns herself with her jewels. (Isa. Isa. 61:10) [emphasis added]

Notes

¹ E. W. Bullinger, Commentary On Revelation (Grand Rapids, MI: Kregel Publications, 1984, 1935), Rev. 19:6-7.

² Robert L. Thomas, Revelation 8-22 (Chicago, IL: Moody Press, 1995), Rev. 19:7.

³ Donald Grey Barnhouse, Revelation (Grand Rapids, MI: Zondervan Publishing House, 1971), 358.

⁴ J. Dwight Pentecost, Things to Come: A Study in Biblical Eschatology (Grand Rapids, MI: Zondervan Publishing House, 1958), 220-221.