I acknowledged my sin unto thee. Conscience once fully awakened, all reticence was broken down. David confessed his sin fully and freely—confessed it as "sin," as "transgression,'' and as "iniquity" (compare the comment on Psalms 32:1).
And mine iniquity have I not hid; rather, did I not hide. I did not attempt to gloss over or conceal the extent of my guilt, but laid my soul bare before thee. Hengstenberg well remarks that the psalmist is probably not speaking of a "making known by the mouth," but of "an inward confession, such as is accompanied with painful repentance and sorrow, with begging of pardon for sin and for the offence rendered to the Divine Majesty."
I said, I will confess my transgressions unto the Lord; and thou forgavest the iniquity of my sin. Upon David's confession, whether it were inward or outward, followed without any interval God's forgiveness—forgiveness which, however, did not preclude the exaction of a penalty required for the justification of God's ways to man (2 Samuel 12:14), and also, perhaps, for proper impressing of the offender himself, who would have been less sensible of the heinousness of his sin, if it had gone unpunished.