God's Word is God's Weapon

On minister preached on Psalm 19 v7: 

"The law of the LORD is perfect, converting the soul: the testimony of the LORD is sure, making wise the simple".

He spoke of God's word in the hand of the Spirit being like the smooth stone which David fired at Goliath from his sling. The stone had been prepared for centuries in the nearby river, worn smooth by other stones and made ready for the day it was to be slung and find an opening in Goliath's armour: so the word has been prepared and made ready as an instrument of the covenant, despite the devil's attempts to distort it (by unreliable versions, Westcott and Hort etc).