For the word of God is living and active, sharper than any two-edged sword, piercing to the division of soul and spirit, of joints and marrow, and discerning the thoughts and intentions of the heart. And before him no creature is hidden, but all are open and laid bare to the eyes of him with whom we have to do.

Hebrews 4:12-13, as quoted in www.ewtn.com - Epistle to the Hebrews