Hebrews 4:10-12

10For he that is entered into his rest, he also hath ceased from his own works, as God did from his. 11Let us labour therefore to enter into that rest, lest any man fall after the same example of unbelief.

12For the word of God is quick, and powerful, and sharper than any twoedged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and is a discerner of the thoughts and intents of the heart.