en_tn/isa/51/08.md

For the moth will eat them up like a garment, and the worm will eat them like wool

God speaks of people who abuse those who are righteous as if they were wool garments, and of their being destroyed as if insects ate them. (See: rc://en/ta/man/jit/figs-metaphor)

my righteousness will be forever

God's "righteousness" here represents him ruling righteously. Alternate translation: "my righteous rule will be forever" or "I will rule righteously forever" (See: rc://en/ta/man/jit/figs-metonymy)

and my salvation to all generations

God's "salvation" here represents the result of his salvation, which is freedom. Being "to all generations" represents lasting forever. Alternate translation: "I will save you, and you will be free forever" (See: rc://en/ta/man/jit/figs-metonymy)