Hebrews 4

For the word of God is living and powerful, and sharper than any two-edged sword, piercing even to the division of soul and spirit, and of joints and marrow, and is a discerner of the thoughts and intents of the heart. v.12

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There is one knife in my kitchen that I always choose to use because it is the sharpest and seems to cut everything so easily, all the other knives I have just leave me frustrated that I rarely even use them.  Well God's word is compared here to a sharp knife, or rather sharper than a double-edged sword.  It does the job no other knife or sword can even do.   Once you realize it's power there's no going back to any other.  It can divide the bone from the marrow.  The marrow is the inside of the bone where the red cells are produced and the joints are the outside hard membrane of the fusion of the bone cells inside- pretty impossible to divide the two.  Even soul and spirit are used so interchangeably by people when referring to them, as well as doing a word study in scripture one will see how similar they are, yet God's word is so sharp that it can divide the soul from the spirit. God's word penetrates us into our deepest thoughts and desires.  It's that sharp that it can discern our thoughts and cut off the bad and keep the good, it is possible to get rid of our sinfulness that seems so intertwined in who we are to leave who He created us to be.  
Do you treat God's word as a dull, rusted butter knife?  The Bible isn't just old literature but is living and active today still!  It speaks to us today just as much as it spoke to the Jews thousands of years ago.  How have you seen God's word come alive to you?  How can it be more so?