Albert Barnes Commentary Isaiah 59:6

"Their webs shall not become garments, neither shall they cover themselves with their works: their works are works of iniquity, and the act of violence is in their hands." — Isaiah 59:6 (ASV)

Their webs shall not become garments – The spider’s web is unfit for clothing; and the idea here is that their works are as unfit to secure salvation as the attenuated web of a spider is for clothing.

The sense is, says Vitringa, that their artificial deceptive arguments are of no use in producing true wisdom, piety, virtue, and religion, or the true righteousness and salvation of people, but are airy speculations. The works of the self-righteous and the wicked; their vain formality, their false opinions, their subtle reasonings, and their traditions, are like the web of the spider.

They cover nothing; they answer none of the purposes of a garment of salvation. The doctrine is that people must have some better righteousness than the thin and gossamer covering which their own empty forms and ceremonies produce .