en_tn_condensed/psa/051/002.md

Wash me thoroughly from my iniquity ... cleanse me from my sin

These two phrases mean the same thing. (See: rc://en/ta/man/translate/figs-parallelism)

Wash me thoroughly from my iniquity

Being acceptable to God is spoken of as being clean. God makes people acceptable by forgiving their sins. Alternate translation: "Wash away all my sin" or "Forgive all my sins so that I will be acceptable to you" (See: rc://en/ta/man/translate/figs-metaphor)

thoroughly

completely, totally

cleanse me from my sin

Being acceptable to God is spoken of as being clean. God makes people acceptable by forgiving their sins. Alternate translation: "Make me clean from my sin" or "forgive me for my sin so that I will be clean" (See: rc://en/ta/man/translate/figs-metaphor)