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.
God’s understanding is limitless … His knowledge is perfect, and … there isn’t a creature anywhere in the universe that isn’t plainly visible to His sight. Nothing is shut before the eyes of God. That is what is called divine omniscience, one of the attributes of God. An attribute, as I have said before, is something which God has declared to be true about Himself.
God has declared by divine revelation that He is omniscient, that He knows everything. The human mind staggers under this truth when we consider how much there is to know and how little we know….
When I received one of the honorary degrees that have been bestowed on me, I said, “The only thing that is learned about me is this pair of glasses.” If a man has his hair slicked back and a pair of learned-looking glasses, they call him a doctor. We don’t know very much, really, and when we consider the great God who knows all there is to know with perfection of knowledge, we stagger under that. The weight of the truth is too much for our minds. AOGII105-106
I stagger and am challenged, but I take comfort in knowing that You know all things. I rest in Your perfect knowledge today. Amen. 
4:13 Second, unbelief is detected by the living Lord. Here the pronoun shifts from the impersonal to the personal: And there is no creature hidden from His sight. Nothing escapes His notice. He is absolutely omniscient. He is constantly aware of all that is going on in the universe. Of course, the important point in the context is that He knows where there is real faith and where there is only an intellectual assent to facts.
13. Nothing in all creation is hidden from God’s sight. Everything is uncovered and laid bare before the eyes of him to whom we must give account.
The emphasis in 4:12–13 shifts from the Word of God to God himself. If God’s Word uncovers everything, then it follows that God himself is fully aware of all things. It is therefore impossible for man to hide his sinful motives in the dark corners of his heart. God knows. He sees everything; even darkness is as light to him (Ps. 139:12).
Moreover, the past, the present, and the future are all alike to God. While we are bound to time and place, God dwells in eternity and transcends all that he has made in his great creation. He created the magnificent constellations in outer space and hung the stars in place. He also created the tiny spider that busily weaves its web. If then his eye is on the sparrow, does he not know the hidden motives of man? Before we open our mouths to speak, God already knows. If we remain silent, he discerns.
No creature is hidden from God’s sight, because with God everything is light—there is no darkness. Man, the pinnacle of God’s creation, is invited to walk in that light, so that he may see clearly. Consider these verses:
Your word is a lamp to my feet and a light for my path. [Ps. 119:105]
I am the light of the world. Whoever follows me will never walk in darkness, but will have the light of life. [John 8:12]
The unbeliever seeks to hide from God but is unable to do so (Jer. 23:24). Secret sins man can hide from his fellow man, but before God sinful man is “uncovered and laid bare.” This latter expression, in the original Greek, refers to the neck. The precise meaning of the word, however, is not clear. Perhaps it indicates that a sinner will have his head pushed up and back so that his face and neck will be exposed to view. Whatever the interpretation may have been, the expression itself is sufficiently clear in context. It is synonymous with the word uncovered and indicates that God’s all-seeing eye rests upon everything.
The clause “to whom we must give account” is rather interesting. The books must be audited, and all the bills, payments, and receipts handed over to be checked. Man must give an account of himself before God, the auditor. The books of man’s conscience are open before God’s eyes. Nothing escapes him.
In the last day sinners may call to the mountains and the rocks, “Fall on us and hide us from the face of him who sits on the throne and from the wrath of the Lamb!” (Rev. 6:16). In the final judgment, everyone must give an account of himself. Only those who are in Christ Jesus will hear the liberating word acquitted.
13 The last description of the word of God is now explained in more direct language: we cannot hide from God the Creator, who knows all about everything and everyone that he has made. “Uncovered and laid bare” translates a remarkably vivid phrase (Montefiore, “naked and prostrate”), in which the second term comes from wrestling and originally denoted “taken by the throat” or “with the neck twisted back,” hence at the mercy of your opponent. (An alternative sense that might still reflect the imagery of the sword is that it pictures a sacrificial victim with its neck bared to the knife.) The sense is that of Psalm 139, with its insistent declaration that God knows everything about us and it is no good trying to escape him.
 Tozer, A. W., & Eggert, R. (2015). Tozer on the almighty god: a 365-day devotional. Chicago, IL: Moody Publishers.
 MacDonald, W. (1995). Believer’s Bible Commentary: Old and New Testaments. (A. Farstad, Ed.) (p. 2169). Nashville: Thomas Nelson.
 Kistemaker, S. J., & Hendriksen, W. (1953–2001). Exposition of Hebrews (Vol. 15, pp. 118–119). Grand Rapids: Baker Book House.
 France, R. T. (2006). Hebrews. In T. Longman III & D. E. Garland (Eds.), The Expositor’s Bible Commentary: Hebrews–Revelation (Revised Edition) (Vol. 13, p. 68). Grand Rapids, MI: Zondervan.