What does it mean that God is omniscient?
The omniscience of God — that He knows all things — is one of the foundational attributes of His being. Scripture reveals it not merely as an abstract theological idea, but as a deeply personal and practical truth: God searches and knows every heart, every thought, every hidden motive, and every unspoken word.
The Scope of God's Knowledge
Morrish's Bible Dictionary lists omniscience among the principal attributes of God revealed in Scripture:
Morrish's Bible Dictionary6. Omniscience. 1 Chr. 28:9; Isa. 42:8-9; Rom. 8:29-30; Heb. 4:13.
Alongside eternity, omnipotence, and omnipresence, omniscience belongs to the very nature of the Godhead. A. J. Pollock captures this:
A. J. PollockThe greatest word that can pass human lips is GOD — GOD from all eternity to all eternity, uncreated, self-sustained, omnipresent, omniscient, omnipotent, THE MIGHTY CREATOR and SUSTAINER, the One in whom we live, and move, and have our being.
Psalm 139: The Great Psalm of Omniscience
The fullest meditation on God's omniscience in all of Scripture is Psalm 139. An article in The Christian's Friend (1875) titled simply "Omniscience" opens:
It is a solemn thought for the soul to be under the searching of Omniscience itself. Yet this is the foundation of solid peace to him who believes the gospel of the grace of God.
It draws out the deeply personal scope of this knowledge:
Every human being has been searched by Omniscience, whether he is conscious of it or not. ... "O Lord, thou hast searched me, and known me. Thou knowest my downsitting and mine uprising, thou understandest my thought afar off. Thou winnowest my path and my lying down, and art acquainted with all my ways."
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.
J. N. Darby summarises the psalm with characteristic conciseness:
Not a thought escapes God. There is, morally speaking, no staying in His presence; but there is no getting out of His presence, nor where He sees not, though conscience might be glad to flee. But this brings in another aspect. He knows all, because also He has formed all. This connects us with the taking perfect notice of us in goodness. He cares for us, watches over every member that is formed, as He knows our every thought; if He does, He has His own too, and these are precious to us.
Not Mere Knowledge, But Searching Power
T. H. Reynolds draws an important distinction — omniscience is not merely a fact about God's mind but an active, penetrating reality:
What is brought before us in this psalm is the searching power of the Spirit of Jehovah. It is not merely the omniscience of God, nor His omnipresence, which is felt when the truth of this psalm is realized, but the soul is brought into the presence of God. The very innermost recesses of the heart are pervaded by an all-searching power.
It is not that anyone might say, "God knows everything; and, of course, He knows all about me." A person might have that consciousness and yet not know what it is to be searched by the Spirit of God. We must come into the sense of it.
Omniscience and the Gospel
The writers repeatedly stress that God's omniscience, far from being a ground for terror, becomes the very foundation of the believer's peace. The 1875 "Omniscience" article brings this out powerfully:
We must recognize then that God knows us, knows us just as we are, knew us from the very outset ... But then the same God has spoken to us in the gospel of the remission of sin. But it is remission of sin according to His omniscience, therefore, of all sin; and if God speaks to us of the righteousness of faith, it is, according to His omniscience, "everlasting righteousness."
The great hindrance to solid peace is a reasoning still in our own minds, as to whether we are really as bad as God knows us to be. ... The gospel is "the gospel of God." It is God who bears witness to the total ruin of man, and it is the same God who bears testimony to the complete efficacy of Christ's work.
Omniscience and God's Purpose
F. B. Hole traces the link between omniscience and God's eternal purpose in Romans 8:
There are five links in the golden chain of divine purpose. The first is foreknowledge, which is rooted in the very omniscience of God — rooted therefore in eternity. Next comes predestination: an act of the divine Mind, which destined those whom He foreknew to a certain glorious place long before they existed in time.
Omniscience Leads to Worship
James Boyd, meditating on Psalm 139, traces the journey from conscience to worship. First the soul is awakened under God's searching eye, and then — discovering that this omniscient God is a God of love — the whole tone changes:
Evidently not for His own information. Why then were we searched? We were searched that we might know ourselves. ... At the first we do not like it, but when we see a little of the good of it we are glad to be searched.
Now he may learn something of the great thoughts of God. God is love, and all the thoughts of God spring from the great love of His heart. No wonder the psalmist says, "How precious also are Thy thoughts unto me, O God! how great is the sum of them! If I should count them, they are more in number than the sand."
Boyd shows how the psalm comes full circle: the soul that once dreaded being known now prays to be searched:
His earnest prayer might be "Search me, O God, and know my heart, prove me, and know my thoughts; and see if there be any grievous way in me, and lead me in the way everlasting."
God's omniscience, then, means far more than that He possesses all facts. It means He searches every heart through and through — every thought, every motive, every unspoken word — and nothing in all creation is hidden from His sight. There is no fleeing from His presence: not in heaven, not in the depths, not in darkness. He knew us before we were formed and sees our whole history as though it were already written.
Yet for the believer, this truth is not a cause for dread but the very ground of peace. Because God already knows the full measure of our ruin, His provision in Christ is not partial or uncertain — it is redemption according to omniscience, and therefore it covers all. His searching is not punitive but purposeful: He searches us that we might know ourselves, abandon our own thoughts for His, and be led in "the way everlasting." The God who knows all things also has His own thoughts toward us, and those thoughts — more in number than the sand — are thoughts of love.