Catechism of the Catholic Church

Freedom and sin. Man's freedom is limited and fallible. In fact, man failed. He freely sinned. By refusing God's plan of love, he deceived himself and became a slave to sin. This first alienation engendered a multitude of others. From its outset, human history attests the wretchedness and oppression born of the human heart in consequence of the abuse of freedom. (387, 401)