'Sinfulness' in the Bible

Did that which is good [the Law], then become death to me? Certainly not! But sin, in order that it might be revealed as sin, was producing death in me by [using] this good thing [as a weapon], so that through the commandment sin would become exceedingly sinful.

Why, then, the Law [what was its purpose]? It was added [after the promise to Abraham, to reveal to people their guilt] because of transgressions [that is, to make people conscious of the sinfulness of sin], and [the Law] was ordained through angels and delivered to Israel by the hand of a mediator [Moses, the mediator between God and Israel, to be in effect] until the Seed would come to whom the promise had been made.