An infidel once said to a servant of Christ who was quoting portion after portion of the Scriptures to him, "Can you prove to me that that is the Word of God?" The man of God replied, "If I ran a sword through your body, would you need any proof of its being a sword?" and went on quoting the Scriptures. Years after, the two met again, and he who had been an infidel had to own that the sword had done its work, and that he needed no further proof that it was the Word of God.
"For the word of God is quick, and powerful, and sharper than any two-edged 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. Neither is there any creature that is not manifest in His sight: but all things are naked and opened unto the eyes of Him with whom we have to do!" Heb. 4:12, 13.