Isaiah 64:6

But we are all as an unclean thing, and all our righteousnesses are as filthy rags; and we all do fade as a leaf; and our iniquities, like the wind, have taken us away.

But we are all as an unclean (thing) ( kaTaamee' (H2931)) - legally unclean as a leper. True of Israel, everywhere now cut off by unbelief, and by God's judgments, from the congregation of the saints.

And all our righteousnesses - plural, 'uncleanness' extended to every particular act of theirs, even to their prayers and praises. True of the best doings of the unregenerate (Philippians 3:6; Titus 1:15; Hebrews 11:6).

(Are) as filthy rags - literally a cloth of removals [ `idiym (H5708), from `eed (H5708), to remove or put away as unclean]; a menstruous rag (Leviticus 15:33; Leviticus 20:18; Lamentations 1:17).

Fade as a leaf - (Psalms 90:5.)