Fine linen is righteous deeds of saints
Here’s what it means
The bride’s clean linen represents the righteous acts granted to and displayed by God’s people.
Why the Bible says it this way
In a prophecy or vision, an object or scene can stand for something else. The surrounding passage often explains the picture.
A helpful detail: The text explains the clothing. The deeds do not replace Christ’s saving grace, since the linen is given to the bride.