This is Ellen White's commentary for Revelation 19:7-9

Revelation 19:7-9 (KJV) Let us be glad and rejoice, and give honour to him: for the marriage of the Lamb is come, and his wife hath made herself ready.
And to her was granted that she should be arrayed in fine linen, clean and white: for the fine linen is the righteousness of saints.
And he saith unto me, Write, Blessed are they which are called unto the marriage supper of the Lamb. And he saith unto me, These are the true sayings of God.

This quote is by Ellen White
Christ Object Lesson
Page 310
The wedding Garment: Christ's Character

By the wedding garment in the parable [Matthew 22:1-14] is represented the pure spotless character with Christ's true follower will possess. To the church it is given "that she should be arrayed in fine linen, clean and white," "not having spot or wrinkle, or any such thing"(Revelation19:8; Ephesians 5:27). The fine linen says the scripture,"is the righteousness of saints" (Revelation 19:8). It is the righteousness of Christ, His own unblemished character, that through faith is impacted to all who receive Him as their personal Saviour.

This is also a Ellen White quote
Education
Page 249
Christ's robe for children and youth

Let the youth and little children be taught to chose for themselves that royal robe woven in heavenly loom the "fine linen clean and white" (Revelation 19:8), which all holy ones of earth will wear. The robe, Christ own spotless character, is freely offers to every human being. But all who receive it will receive and wear it here.