OET interlinear PSA 51:3

uW Translation Notes:

Note 1 topic: grammar-connect-words-phrases

כִּֽי

(Some words not found in UHB: that/for/because/then/when transgressions_of,my I know and,sin_of,my [is]_before,me ever )

Here the word For introduces not a reason but an admission. Alternate translation: [Indeed,] or [Admittedly,]

Note 2 topic: writing-pronouns

פְ֭שָׁעַ⁠י אֲנִ֣י אֵדָ֑ע

(Some words not found in UHB: that/for/because/then/when transgressions_of,my I know and,sin_of,my [is]_before,me ever )

David is stating the pronoun I separately, even though the verb translated as I know already includes this meaning. He is doing that because he is confronting himself with the fact of his transgressions. Alternate translation: [I know very well that I have committed transgressions]

Note 3 topic: figures-of-speech / metaphor

וְ⁠חַטָּאתִ֖⁠י נֶגְדִּ֣⁠י תָמִֽיד

(Some words not found in UHB: that/for/because/then/when transgressions_of,my I know and,sin_of,my [is]_before,me ever )

David is speaking of his sin as if it were actually an object that was always before him or in front of him. If it would be helpful in your language, you could state the meaning plainly. Alternate translation: [and I am always conscious of my sin]