Hebrews 4:12

12 For the word of God is living and active, sharper than any two-edged sword, piercing to the division of soul and of spirit, of joints and of marrow, and discerning the thoughts and intentions of the heart.

Hebrews 5:14

14 But solid food is for the mature, for those who have their powers of discernment trained by constant practice to distinguish good from evil.