This verse is both by Jewish and Christian, by ancient and later, interpreters, generally and most truly understood of original sin; which he here mentions as an aggravation of his crime: and the sense of the place is this, Nor is this the only sin which I have reason to acknowledge and bewail before thee; for this filthy stream leads me to a corrupt fountain; and upon a serious review of my heart and life I find that I am guilty of innumerable other sins, and that this heinous crime, though drawn forth by external temptations, yet was indeed the proper fruit of my own filthy and vile nature, which, without the restraints of thy providence or grace, ever was, and still is like to be, inclinable and ready to commit these and ten thousand other sins, as occasion offers itself; for which contrariety of my very nature to thine, thou mayst justly loathe and condemn me; and for which I humbly beg thy pardon and grace. Conceive me, Heb. warm or cherish me in the womb, before I was shapen or formed there.
Related Commentaries of Psalms 51:5
Psalms 51:5
5 Behold, I was shapen in iniquity; and in sin did my mother conceivea me.