The heart‑searching power of the word attests to its divine origin

           First Effect.  The word of God hath a heart-searching power, whereby it ransacks and rifles the consciences of men.  It looks into the most secret transactions of the heart and tells us what we do in our bed-chamber—as Elisha did by the king of Syria, II Kings 6:12.  It cometh where no prince’s warrant can empower his officer to search, I mean the heart.  We read that Christ came to his disciples ‘when the doors were shut, and stood in the midst of them,’ John 20:19.  Thus the word—when all doors are shut, that men have no intelligence what passeth within the breasts of men—comes in upon the sinner without asking him leave, and stands in the midst of his most secret plots and counsels, there presenting itself to his view, and saith to him as Elisha to Gehazi, ‘Went not my eye with thee when thou didst this and that?’  How often doth the sinner find his heart discovered and laid out of all its folds by the word preached, as if the minister had stood at his window, and seen him what he did within doors, or some had come and told tales of him to the preacher?  Such I have known, that would not believe to the contrary, but that the min­ister had been informed of their pranks, and so leveled his discourse particularly at their breasts, when he hath been as ignorant of their doings as of theirs that live in America, and only shot his reproofs like him that smote Ahab, who drew his bow at a ven­ture, without taking aim at the person of any.  From whence can this property come but [from] God, who claims it as his own incommunicable attribute, ‘I the Lord search the heart?’ Jer. 17:10.  God is in the word, and therefore it findeth the way to get between the joints of the harness, though sent at random out of man's bow.  If any creature could have free ingress into this retiring room of the heart, the devil, being a spirit, and of such a piercing, prying eye, were the most likely to be he; yet even he is locked out of this room, though indeed he can peep into the next.

           Now if God can only search the heart, then the word which doth the same can come from no other but God himself.  Who indeed can make a key to this lock of the heart, but he that knoweth all the wards of it?  Suppose you did lock up a sum of money in a cabinet, and none but one in all the world besides yourself besides yourself were privy to the secret place where you lay this key.  If you then should find the key taken away, and the cabinet opened and rifled, you would soon conclude whose doing it was.  Why thus, when you find your heart disclosed, and the secret thoughts therein laid open unto you in the word, you may easily conclude that God is in it.  The key that doth this is of his making who is the only one besides yourselves that is privy to the counsels of your hearts, that seeth all the secret traverses of your in­ward man.  Who but he can send a spy so directly to your hiding-place, where you have laid up your treasures of darkness out of the world's sight?  There are two secrets that the word discloseth:—

           First.  What a man’s own heart knoweth, and no creature besides.  Thus Christ told the woman of Sa­maria what her neighbours could not charge her with; from which she concluded him to be a prophet—a man of God.  And may we not conclude the Scripture to be the word of God, that doth the same?

           Second.  Those things which a man’s own heart is not privy to.  God is said to be ‘greater than our hearts, and knoweth all things,’ I John 3:20.  He knows more by us than we by ourselves.  And doth not the word dive to the bottom of the heart, and fetch up that filth thence, which the eye of the conscience never had the sight of before, nor ever could without the help of the word?  ‘I had not known lust, except the law had said, Thou shalt not covet,’ Rom. 7:7.  And if the word findeth that out which escapeth the scrutiny of man’s own heart, doth it not prove a Deity to be in it?  So argueth the apostle, I Cor. 14:25, speak­ing of the power the word preached hath to lay open the heart: ‘Thus are the secrets,’ saith he, ‘of his heart made manifest; and so, falling down on his face, he will worship God, and report that God is in you of a truth.’