Hebrews 4:12-13

12For the word of God is quick, and powerful, and sharper than any twoedged 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. 13Neither 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. (Hebrews 4:12‑13)Altogether this is a very remarkable scripture, as setting forth the all-searching character of the word of God, when it is applied to us in the power of the Holy Ghost. It is necessary to observe that it is its action on Christians which the apostle has in view. He has been pointing out that there remaineth a rest for the people of God, that it is not therefore to be looked for here in the wilderness, but that it is future, that God's rest, in fact, into which He is bringing His people, is in heaven. Joined to this is the exhortation, " Let us labor [use diligence] therefore to enter into that rest, lest any man fall after the same example [as shown out in the case of the children of Israel] of unbelief."
Thereupon he proceeds to speak of the provision God has made to search our hearts by the living action of His Word upon our souls, which, penetrating into all the secret recesses of our being, detects every tendency to unbelief and departure from God, and reveals everything cherished there unsuitable to Him. Nothing whatever can escape it, when once it finds entrance into our hearts and consciences. It is, indeed, the light which makes everything manifest, as well as that which, sharper than any two-edged sword, cuts down between the most hidden parts of our nature, and exposes everything to view. Then it is that the words follow: "Neither is there any creature that is not manifest in His sight," etc. The reader will observe this striking connection between God Himself and the Word. We might have expected "its sight"; but no, it is "His sight." The reason is, God and His word cannot be disjoined. When He speaks, when His word comes home to us, it is Himself we hear speaking; we are brought into His presence, and it is only as being consciously there, that we can judge everything in the thoughts and intents revealed by the Word as contrary to Him, according to His holy nature. Even God's own word remains a dead letter until it comes to us as a revelation of Himself and of His mind. This at once explains to us why we read, in verse 13, "His sight," and also that " all things are naked and opened [laid bare] unto the eyes of Him with whom we have to do." Truly we are, in this sense also, in the light as God is in the light, and we can, blessed be His name, be there in perfect peace and liberty, when we remember that "the blood of Jesus Christ His Son cleanseth us from all sin."