What does it mean that God is omniscient? The roots of the word communicate that God has a knowledge (scientia) of all things (omnia). In some ways, to express God’s omniscience as a knowledge of all things can fall short of apprehending its grandeur and majesty. To understand God’s omniscience rightly, the first thing we must affirm is that God knows Himself.
God’s omniscience follows from the foundation of God’s knowledge of Himself. As the Apostle Paul says in 1 Corinthians 2:11, “For who knows a person’s thoughts except the spirit of that person, which is in him? So also no one comprehends the thoughts of God except the Spirit of God.” God is simple—that is, without parts or composition of any kind—and has a perfect and complete knowledge of Himself. Theologians call this God’s “knowledge of simple intelligence.”
Because God knows Himself, He knows all things that can possibly be because He knows all things that He could possibly create. In man, logical possibility and practical possibility are separate things. So, a client may want a certain product that is logically possible, but engineers may have to give the bad news that it is not practically possible. The client’s idea could be accomplished in theory, but the engineers cannot do it. However, in God these two things are not distinct. Whatever can be, can be created by God. God knows Himself, therefore He knows all things possible.
Of all the things that could possibly be, God willed to create the world and everything in it “according to its kind” as He, the Master Artisan, saw fit (Gen. 1:11, 12, 25, 31). But God did not simply will the existence of things and leave them to be. God decreed “the end from the beginning” (Isa. 46:10) and “works all things according to the counsel of his will” (Eph. 1:11). Because God willed the existence of all that is and has decreed the unfolding history of all things great and small, from the beginning to the end, knowing the end from the beginning, therefore we can also speak of God’s “knowledge of vision.”
God’s knowledge of vision is His knowledge of all that will be in the world, which He willed to create and which future He has decreed. God not only knows all that can possibly be, but He also knows all that He has decreed to be. His knowledge of vision is, as the Westminster Confession and Second London Baptist Confession state, “infinite, infallible, and independent upon the creature, so as nothing is to him contingent, or uncertain” (WCF/2LCF 2.2). God’s knowledge is not acquired from anything outside of Him, because nothing can be apart from Him bringing it into being, and nothing can take place apart from His decree. Therefore, because God’s knowledge of simple intelligence reaches to all possibilities, and because God’s knowledge of vision reaches to all reality, God’s omniscience is truly an omni-science. If we express God’s omniscience as “God knows all things,” we must be careful not to unintentionally limit God’s knowledge by making it relative to all things created. God’s omniscience is as much greater than creation as God Himself is greater than creation.
How does God’s omniscience affect our lives in a practical way? It is first a threat, then a comfort. Because God knows all things, He knows the sin of all people in its fullness. As the writer to the Hebrews says, “No creature is hidden from his sight, but all are naked and exposed to the eyes of him to whom we must give account” (Heb. 4:13). Indeed, God’s knowledge reaches to our thoughts, desires, intents, and inclinations. God told the Israelites that He knew their thoughts: “I know the things that come into your mind” (Ezek. 11:5). The God “who knows the heart” (Acts 15:8) knows the sin of all people, and they will give an account for their disobedience to Him.
But there is hope and comfort for all who believe in Jesus Christ because God’s covenant promise is to “remember their sin no more” (Jer. 31:34). The God who knows your sin also knows your Savior. Indeed, the Apostle John used the greatness of God’s knowledge as a reassurance for afflicted consciences. In 1 John 3:20 he says, “Whenever our heart condemns us, God is greater than our heart, and he knows everything.” God knows everything, even when our hearts forget. God is greater than our hearts, and His omniscience is a comfort to those who seek refuge and refreshment in God’s mercy in Christ Jesus. Your heart may forget God’s covenant, but He will not.
God’s omniscience is a comfort for God’s children because He knows us and cares for us. David marveled at God’s knowledge, recognizing his own limitations by comparison and worshiping God as a result.
You know when I sit down and when I rise up;
you discern my thoughts from afar.
You search out my path and my lying down
and are acquainted with all my ways.
Even before a word is on my tongue,
behold, O Lord, you know it altogether.
You hem me in, behind and before,
and lay your hand upon me.
Such knowledge is too wonderful for me;
it is high; I cannot attain it. (Ps. 139:2–6)
Let us follow David’s example, rejoicing that the God who knows Himself knows us, and by His decree, providence, and power, He will bring all things to their perfect end for His own glory and our blessedness in Him.
Ligonier Ministries