What does it mean that God is omniscient?

If man has thus learned to see through material barriers, through means God has provided, how much greater in this respect must be the ability of God! Does it not teach us therefore the omniscience of the eternal God? - that is, His absolute knowledge of everything. "0 Lord, Thou hast searched me, and known me. Thou knowest my downsitting and mine uprising, Thou understandest my thought afar off. Thou compassest my path and my lying down, and art acquainted with all my ways. For there is not a word in my tongue, but lo, 0 Lord, Thou knowest it altogether. Thou has beset me behind and before, and laid Thine hand upon me. Such knowledge is too wonderful for me: it is high, I cannot attain unto it" (Psalm 139:1-6). Peter too confessed this infinite omniscience to be true of the Lord Jesus Christ, "Lord, Thou knowest all things" ( John 21:17).

Coming to omniscience, it is noticeable how the word infinite covers all these glorious attributes of God. Limitless as to time, power, and space, He is the same as to knowledge. There is a close link between omniscience and omnipotence, for, to compass the ages, and foretell what will come to pass in dim and distant times, God must have the hearts of all men under His direct control. Known unto God are all His ways from the beginning, and as we trace these ways, and see how He makes both sin and Satan to serve Him, we can understand how He works out His purposes of eternity in connection with the failure of the creature. This is a matter worthy of our deepest thought, concerning, as it does, His marvellous grace, in relation to us in all our helplessness and ruin. The great outstanding proof of this is the Cross, where our God has taken account of Man's darkest and worst crime in crucifying His Son, to bring in, for man, His own richest thoughts of blessing. He both knows and fore-knows; Prescience and omniscience are His, because He is GOD. "Behold the former things are come to pass, and new things do I declare: before they spring forth I tell you of them" (Isaiah 42:9). "For the Lord searcheth all hearts and understandeth all the imaginations of the thoughts" (1 Chron. 28:9). (See, for its action in our Lord, John 2:24-25; and compare Jer. 17:10). This wonderful feature of the divine majesty fills the heart with holy awe, and is productive of richest praise. The Bible is full of the all-knowing, all-pervading marks of the eternal God, and, when we reach the holy Gospels, we are filled with wonder, love, and praise, as we behold every characteristic feature of Godhead coming out in a Man — our Lord Jesus Christ.

Like His wealth and wisdom, this is infinite. He both knows and fore-knows; He is both Prescient and Omniscient. His knowledge is linked with His Omnipresence as related to the dimensions of space — above; beneath; around; and with the three variants of time — past; present; and future. This also links with His Omnipotence, for to know what will take place at a future time necessitates that all is under His control. He telleth the number of the stars and numbers the hairs of our heads. "He that planted the ear, shall he not hear? he that formed the eye, shall he not see? He that chastiseth the heathen, shall not he correct? he that teacheth man knowledge shall he not know?" Ps. 94:9-10. "For whom he did foreknow, he also did predestinate to be conformed to the image of his Son." Rom. 8:29. "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. 4:13. But see how it works out in God incarnate — the Man of the Gospels. He saw Nathanael under the fig tree, John 1:48. "Lord thou knowest all things; thou knowest that I love thee," John 21:17. He knew the movements of heaven, earth and hell. Luke 10:18; Luke 16:23-31. His eye was upon the fish in the sea and He sent one to Peter with the money in its mouth to meet the pressing need, Matt. 17:27. "For the LORD searcheth all hearts, and understandeth all the imaginations of the thoughts." 1 Chr. 28:9. "For out of the heart proceed evil thoughts, murders, etc." Matt. 15:19. He foreknows and foretells. He told them that Jerusalem would fall to the Romans in desolation, distress and wrath. Luke 21:20-24. This came to pass forty years after the Cross. Many other things did He foretell which are about to be fulfilled. Here again is a depth that knows no sounding.

The English word ‘providence’ has its origin in the Latin word pro video, which literally means to see in advance. It is obvious that no human being is able to see things before they take place. Solomon says: ‘for thou knowest not what a day (that is, the next day) will bring forth’ (Prov. 27:1). We may have a hope or expectation that certain things could possibly happen but we will never have pre-knowledge. Only our God is a ‘God of knowledge’ (1 Sam 2:3). He is the only one to really foresee things before they happen. He knows the future. In fact, He knows the end of all things, and has done so even before the created universe came into being.

All is known to the Lord. The unseen world as well as the future; all eternity is known to Him. All is naked and open before Him. He knoweth the hearts of men, yea even our thoughts afar off, before they ever pass through our finite minds.

Every human being has been searched by Omniscience, whether he is conscious of it or not. This will be made clear "in the day when God will judge the secrets of men." The searching of "the thoughts and intents of the heart" by the word of God now, is the means of bringing God's knowledge into application to our conscience before "that day." And when this is the case, then are we conscious that our thoughts are understood afar off, and that there is not a word in the tongue, but the Lord knoweth it altogether. He has "beset us behind and before." He can look backward, and He can look forward also. All our history is before Him, as if it had been written after we had run our course. "O Lord, thou hast searched me," is the language of the Psalmist; not "thou art doing it now, or wilt do it hereafter, but thou hast done it already." "O Lord, thou hast searched me, and known me. Thou knowest my downsitting and mine uprising, thou understandest my thought afar off. Thou winnowest (marg.) my path and my lying down, and art acquainted with all my ways." (vv. 1-3.)

Every human being has been searched by Omniscience, whether he is conscious of it or not. This will be made clear "in the day when God will judge the secrets of men." The searching of "the thoughts and intents of the heart" by the word of God now, is the means of bringing God's knowledge into application to our conscience before that day. And when this is the case, then are we conscious that our thoughts are understood afar off, and that there is not a word in the tongue, but the Lord knoweth it altogether. He has "beset us behind and before." He can look backward, and He can look forward also. All our history is before Him, as if it had been written after we had run our course. "O Lord, Thou hast searched me," is the language of the Psalmist - not "Thou art doing it now, or wilt do it hereafter, but thou hast done it already." "O Lord, thou hast searched me and known me. Thou knowest my downsitting and mine uprising, Thou understandest my thought afar off. Thou winnowest [marg.] my path and my lying down, and art acquainted with all my ways" (v. 1-3).

Every detail of our lives is known to God; every movement of the body, and the thought of the mind and heart at its inception. Every moment of the day of activity, the time of our rest; yea, all the ways that distinguish us down here are thoroughly known to Him. Before the word that has been conceived has left the tongue it is known to God. He knows it altogether: the motive and spirit of its conception, the object of its transmission. Others may be deceived by its sound; we may deceive ourselves regarding the motive for it, but He knows everything about it perfectly. How good it is to go through life in the consciousness of these things. O that we were constantly conscious that we have to do with God in everything. Sometimes God will not let us go forward; at other times He will not let us go back, for He besets behind and before. In His governmental ways with us He knows how to keep us from ways that would dishonour Him and bring shame and sorrow to our poor hearts; and betimes He puts, His hand upon us, so that we might feel that it is Himself that is dealing with us in wisdom and in love. Do we feel with the Psalmist that the knowledge of these things is too wonderful for us? How great God is! and yet to think He stoops to deal with puny mortals; with such insignificant individuals as we are. It is indeed wonderful that God should be so interested in the creatures of his hand. Yet it is so!

God knows exactly what we are, He knows every thought, every motive, and nothing is or can be hidden from Him. In this assurance the child of God walks; he knows God is looking into his heart, and sees all things. He does not fear the look of God, who is light; nay, he is glad of it. All that he is in himself, his God knows, and he is aware that he can never take God by surprise by what he does, because God knows what he is, though very often he is a wonder of evil to himself. There is not the thinnest gossamer wail between him and God, nor yet a single step which he can ever take away from the eye of God.

We have read in Psalm 138:8 of the works of God's hands. Now the psalmist considers God's works in the details of his own existence, and because God is Creator, He therefore penetrates those details fully and perfectly. Nothing is hid from Him, including the very thoughts of the heart.