The Bible teaches that God is all-knowing or omniscient. The word omniscient comes from two Latin words: omni signifying all, and scientia signifying knowledge. When we say that God is omniscient, it means that he has perfect knowledge of all things. He does not have to learn anything, and he has not forgotten anything. God does not have to reason things out, find things out, or learn them gradually. He knows everything that has happened and everything that will happen. God also knows every potential thing that might happen. God even knows those things that humankind has yet to discover. This knowledge is absolute and unacquired. The omniscience of God means that he has perfect knowledge, perfect understanding, and perfect wisdom as to how to apply that knowledge.
As we stop and think about the immensity of this concept, two thoughts become clear. First, we see that studying attributes is an important and beneficial process. God wants to be known, and he wants us to study him and know more about him. The second point is the flip side of that thought. The more we study God, the more we know our knowledge of God is imperfect. Think about it. It is impossible to fully understand a God who knows everything. He doesn't need to learn. He doesn't need to figure things out. He doesn't get caught by surprise. He is an immense God.
So let's talk about this God of knowledge. That's what the Bible calls him. In the prayer of Hannah, the mother of Samuel, we read, "Talk no more so very proudly, let not arrogance come from your mouth; for the Lord is a God of knowledge, and by him actions are weighed" [1 Samuel 2:3]. The psalmists wrote, "O Lord, you have searched me and known me. You know when I sit down and when I rise up; you discern my thoughts from far away. You search out my path and my lying down, and are acquainted with all of my ways. Even before a word is on my tongue, O Lord, you know it completely. You hem me in, behind and before, and lay your hand upon me. Such knowledge is too wonderful for me; it is so high that I cannot attain it" [Psalm 139:1-6 ESV].
So not only is God the God of knowledge. There is no limit to that knowledge. The psalmists wrote of God's infinite knowledge, "Great is our Lord, and mighty in power; his understanding is infinite" [Psalm 147:5]. Infinite knowledge is a concept we simply cannot grasp. Think about the fact that what God knows, he has known from eternity. Infinite knowledge means that God's knowledge is without limit. The apostle Paul declared, "Oh, the depth of the riches both of the wisdom and knowledge of God! How unsearchable are His judgments and His ways past finding out!" [Romans 11:33]. The psalmists declared, "Great is our Lord, and abundant in power; his understanding is beyond measure" [Psalm 147:5 ESV].
Infinite knowledge is not like human knowledge. That's almost so obvious that it doesn't need to be stated. God is infinite. We are finite. Isaiah described this when he writes, Isaiah 55:8-9 - "'For My thoughts are not your thoughts, Nor are your ways My ways,' says the LORD. 'For as the heavens are higher than the earth, So are My ways higher than your ways, And My thoughts than your thoughts.'" So, as if infinite wasn't enough, God's knowledge is also perfect. Remember, we refer to God's attributes as the perfections of God. The knowledge of God is exactly that. In the book of Job, a man called Elihu said, "Do you know the balance of the clouds, those wondrous works of him who is perfect in knowledge?" [Job 37:16].
As we think about this idea of infinite and perfect knowledge, we realize that God has no teacher. Normally, that's a bad sign when you say about a person that they can't be taught. But because the knowledge of God is perfect, he has no instructor, no professor. There is no knowledge that someone else has that needs to be taught to God. The Bible says, "Can anyone teach God knowledge, in that He judges those on high?" [Job 21:22]. Paul stated the same truth. "For who has known the mind of the Lord or who became his counselor?" [Romans 11:34]. If God can't be taught, neither does God have to investigate anything. He doesn't need to Google or Wikipedia something. Job says, "For he knows those who are worthless and he sees iniquity without investigating" [Job 11:11 NASB].
Now, as all these things are true, how does this concept apply to us? What does this mean to me personally, in my location, in today's day and age? Well, first, God is aware of what is presently happening here on earth. Even though he is that same God of Adam and Eve, the same God of Abraham, the same God of the Old Testament Jews, and the same God of the New Testament Church, even the latest of those events still happened over 2000 years ago. So we might be tempted to think that God cannot relate. But hear this. "The Lord said, 'I have surely seen the affliction of my people who are in Egypt, and have given heed to their cry because of their taskmasters, for I am aware of their suffering'" [Exodus 3:7 NASB]. God expressed care for his people when they were in bondage in Egypt. And yes, that was thousands of years ago, but he has that same care for us today.
He also knows things from the past, and he is the same God of those people in the past. But the flip side is that he is the God of the future. Because God exists outside of time, he knows everything that will happen. Isaiah writes, we read the Lord saying that he declared "the end from the beginning, and from the ancient times things which have not been done, saying, 'My purpose will be established, and I will accomplish all My good pleasure'" [Isaiah 46:10 NASB]. An example of that which has already happened was God's prediction of Abraham. The Bible says, "Abraham will surely become a great and powerful nation, and all the nations on earth will be blessed through him. For I have chosen him, so that he will direct his children and his household after him to keep the way of the Lord by doing what is right and just, so that the Lord will bring about for Abraham what he has promised him" [Genesis 18:18-19 NIV].
Scripture speaks symbolically of the eyes of God seeing all things. "For the eyes of the Lord move to and fro throughout the earth that He may strongly support those whose heart is completely His" [2 Chronicles 16:9 NASB]. Now, the context of this verse deals with the righteousness of man, but the concept behind it is God's perfect knowledge. He knows deep inside the heart of every person. So he is the same God in the past, he is the same God in the future, and he is the same God today. He is able to see sin. We cannot hide from his knowledge.
But to make this application even more personal, God knows what evil people think. Job tells us, "Therefore He knows their works, and He overthrows them in the night" [Job 34:25 NASB]. And this is where we see some of the overlap of God's attributes; the combination of perfect knowledge and perfect wisdom and perfect judgment. Only a God who is perfect in knowledge would be competent to judge humanity. The Bible speaks of that Day of Judgment when the Lord will judge all humanity. Logically, for God to judge righteously, he must know all things. When people realize they will have to stand one day before an all-knowing God, this should cause them to evaluate the way they live their lives. Judgment is coming, and people need to live in light of that truth. Jesus said, "For by your words you will be justified, and by your words you will be condemned" [Matthew 12:37].
So, on the one hand, mankind should take the warning seriously. Because God knows everything, the warnings that he gives humankind are pretty important. But on the other hand, and again, when you look at this in the overlap of attributes, since the God of knowledge knows what will happen in the future, any warning he gives comes from the God of love and they are for our benefit. This is a great comfort for the believer in the omniscience of God. In all of the problems we the believer may face, we are told by Jesus that "Your Father knows" [Matthew 6:8].
There's also great intimacy in God's knowledge. The Lord searches every heart. The Bible says, "For the Lord searches every heart and understands every motive behind the thoughts. If you seek him, he will be found by you; but if you forsake him, he will reject you forever" [1 Chronicles 28:9 NIV]. So not only do we derive comfort from his knowledge. We derive security. The believer may rest secure in the knowledge that God knows everything about them. Nothing about any of us will take God by surprise. No one can tell him anything that would cause him to cast us out of his presence. He thoroughly knows us. "Whenever our heart condemns us, for God is greater than our hearts, and he knows everything" [1 John 3:20 CSB].
As we examine what the Scripture has to say about the extent of the knowledge of God, several things become clear. First, God is a God of infinite knowledge. There is nothing that he is not aware of. God is not like human beings in his knowledge. He cannot learn anything, does not need to be taught, and does not make any mistakes. Consequently, he is able to righteously judge humanity for he knows the thought as well as the deed. His omniscience also allows him to predict the future. He knows everything that will happen before it occurs. This is a great security for the believer in the omniscience of God. He knows the needs of each believer, and he promises to meet all of those needs. All those who have put their trust in him are comforted by the thought of God's omniscience.
Now, to further study this concept that God is all-knowing, let's look at some passages in Scripture that express God's omniscience, that he knows everything. From them, we can gain greater insight into the knowledge of God. One key to knowing everything is foreknowledge. This means that God knows everything that will happen before it occurs. Scripture says, "For those God foreknew he also predestined to be conformed to the likeness of his Son, that he might be the firstborn among many brothers. And those he predestined, he also called; those he called, he also justified; those he justified, he also glorified" [Romans 8:29-30 NIV]. In the book of Acts, it states, "This man was handed over to you by God's set purpose and foreknowledge; and you, with the help of wicked men (or of those not having the law, that is, the Gentiles), put him to death by nailing him to the cross" [Acts 2:23 NIV]. Peter wrote, "Who have been chosen according to the foreknowledge of God the Father, through the sanctifying work of the Spirit, for obedience to Jesus Christ and sprinkling by his blood: Grace and peace be yours in abundance" [1 Peter 1:2 NIV].
So not only does God know what will happen in the future. He knows when it will happen in advance. He has foreseen, that is, he sees everything ahead of time. Paul wrote, "The Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel beforehand to Abraham, saying, 'All the nations will be blessed in you'" [Galatians 3:8 NASB]. Peter said, "Foreseeing this, David spoke of the resurrection of the Messiah, saying, 'He was not abandoned to Hades, nor did his flesh experience corruption'" [Acts 2:31]. Interestingly, God did not keep this knowledge to himself. God tells us what will happen ahead of time. "In this way, God fulfilled what he had foretold through all the prophets that his Messiah would suffer" [Acts 3:18 NIV].
And it's not like God just knew things in advance, but he planned on things in advance as well. The word foreordained speaks of events that God determined ahead of time. "But with the precious blood of Christ, as of a lamb without blemish and without spot. He indeed was foreordained before the foundation of the world, but was manifest in these last times for you" [1 Peter 1:19-20]. Paul wrote, "Who has saved us and called us to a holy life, not because of anything we have done but because of his own purpose and grace. This grace was given us in Christ Jesus before the beginning of time" [2 Timothy 1:9 NIV].
These biblical words made clear that God knows everything. They are foreknowledge, foreseeing, foretelling, and foreordained. Foreknowledge means God knows what will happen before it occurs. Foreseeing has the idea of God seeing events before they actually take place. Foretelling means that God perfectly predicts what will happen before it does happen. And the word foreordained means that God has ordained events to occur in the future. Because he has foreordained them, they will happen. These words confirm the biblical truth that God knows everything: past, present, and future.