For I. — There is an emphatic pronoun in the first clause which we may preserve, at the same time noticing the difference between the violation of the covenant generally in the term transgressions in the first clause, and the offence which made the breach in the second. (See Note Psalms 51:1.) Because I am one who is conscious of my transgressions, and (or, possibly, even) my offence is ever before me.
The thought that he had been unfaithful to the covenant was an accusing conscience to him, keeping his sin always before his eyes, and until, according to his prayer in Psalms 51:1-2, he was received back into conscious relationship again, his offence must weigh upon his mind. This explanation holds, whether an individual or the community speaks.