Part of God’s sovereignty is His omniscience. This means that God knows all things. He doesn’t merely know the things that are, or the things that have been, but He also knows all that will be. Even further, I would add, God knows all things that could have been if He had wanted them to be so. God knows everything there is to know including the things that are not a reality. The ultimate answer to why God knows all things is because He is the one who ordained all things. God does not merely look into the future, He writes the future. More accurately I should say He has already wrote the future. God exists outside of time and views the past the present and the future like one masterful painting that He has already finished.
Let’s look at the Scripture and let it speak for itself about God’s omniscience.
"1O LORD, you have searched me and known me! 2You know when I sit down and when I rise up;you discern my thoughts from afar. 3You search out my path and my lying downand are acquainted with all my ways. 4Even before a word is on my tongue,behold, O LORD, you know it altogether. 5You hem me in, behind and before,and lay your hand upon me. 6Such knowledge is too wonderful for me;it is high; I cannot attain it."
"Too high" indeed! God’s knowledge is tremendously superior to that of His creation. There is nothing that escapes the knowledge of God. Verse 5 stands out strongly to me when David says "You hem me in, behind me and before, and lay your hand upon me." How in credible that God is behind us and in front of us as well as lays His very hand upon us. God Is God of our coming and going and indeed He directs our every step.
The omniscience of God is well displayed in the person of Jesus, the "God-man." In the gospel of John chapter 4, Jesus has an encounter with a woman of Samaria and reveals His detailed knowledge of a person whom He had never met.
"16Jesus said to her, "Go, call your husband, and come here." 17The woman answered him, "I have no husband." Jesus said to her, "You are right in saying, 'I have no husband'; 18for you have had five husbands, and the one you now have is not your husband. What you have said is true." 19The woman said to him, "Sir, I perceive that you are a prophet."
So enamored with the knowledge that Jesus had of her life the woman went into the town and proclaimed "Come, see a man who told me all that I ever did. Can this be the Christ?" (Jn. 4:29)
"But Jesus, knowing their thoughts, said, "Why do you think evil in your hearts?"
"But he, knowing their thoughts, said to them, "Every kingdom divided against itself is laid waste, and a divided household falls."
Above are two example out of a number we could pull out where Jesus as God knows the thoughts of those around Him.
It only makes sense that God as creator would no everything about His creation. God, afterall, is the designer of the earth and all that is in it. Henry Ford knew all the ends and outs of the Model-T, why because he designed it and put it all together. In Job chapter 38 God outs Job in his place because of his questioning God. God asks Job a series of piercing questions that reveal God’s omnipotent power and by default His omniscience of all things as the author of all that exists.
1Then the LORD answered Job out of the whirlwind and said: 2"Who is this that darkens counsel by words without knowledge? 3Dress for action
like a man;I will question you, and you make it known to me.
4"Where were you when I laid the foundation of the earth?Tell me, if you have understanding. 5Who determined its measurements--surely you know!Or who stretched the line upon it? 6On what were its bases sunk,or who laid its cornerstone, 7when the morning stars sang togetherand all the sons of God shouted for joy?
8"Or who shut in the sea with doorswhen it burst out from the womb, 9when I made clouds its garmentand thick darkness its swaddling band, 10and prescribed limits for itand set bars and doors, 11and said, 'Thus far shall you come, and no farther,and here shall your proud waves be stayed'?
12"Have you commanded the morning since your days began,and caused the dawn to know its place, 13that it might take hold of the skirts of the earth,and the wicked be shaken out of it? 14It is changed like clay under the seal,and its features stand out like a garment. 15From the wicked their light is withheld,and their uplifted arm is broken.
16"Have you entered into the springs of the sea,or walked in the recesses of the deep? 17Have the gates of death been revealed to you,or have you seen the gates of deep darkness? 18Have you comprehended the expanse of the earth?Declare, if you know all this.
19"Where is the way to the dwelling of light,and where is the place of darkness, 20that you may take it to its territoryand that you may discern the paths to its home? 21You know, for you were born then,and the number of your days is great!
22"Have you entered the storehouses of the snow,or have you seen the storehouses of the hail, 23which I have reserved for the time of trouble,for the day of battle and war? 24What is the way to the place where the light is distributed,or where the east wind is scattered upon the earth?
25"Who has cleft a channel for the torrents of rainand a way for the thunderbolt, 26to bring rain on a land where no man is,on the desert in which there is no man, 27to satisfy the waste and desolate land,and to make the ground sprout with grass?
28"Has the rain a father,or who has begotten the drops of dew? 29From whose womb did the ice come forth,and who has given birth to the frost of heaven? 30The waters become hard like stone,and the face of the deep is frozen.
31"Can you bind the chains of the Pleiadesor loose the cords of Orion? 32Can you lead forth the Mazzaroth
in their season,or can you guide the Bear with its children? 33Do you know the ordinances of the heavens?Can you establish their rule on the earth?
34"Can you lift up your voice to the clouds,that a flood of waters may cover you? 35Can you send forth lightnings, that they may goand say to you, 'Here we are'? 36Who has put wisdom in the inward parts
or given understanding to the mind?
37Who can number the clouds by wisdom?Or who can tilt the waterskins of the heavens, 38when the dust runs into a massand the clods stick fast together?
39"Can you hunt the prey for the lion,or satisfy the appetite of the young lions, 40when they crouch in their densor lie in wait in their thicket? 41Who provides for the raven its prey,when its young ones cry to God for help,and wander about for lack of food?
God designed you and me and all that we see, and He intimately knows how all of it works. God is the chief scientist if you will, as much as that statement would gripe an atheist.
So we see that Scripture does in deed teach the omniscience of God. The given examples are but a drop in a very, very large bucket about what the Bible has to say about the omniscience of God. It would not be hard to find numerous more examples of God’s omniscience, but I am not trying to give an exhaustive list. My intent was to show that Scripture does indeed teach the omniscience of God. I think that has been clearly demonstrated.