One of the greatest misunderstandings among Christians today is the scope and breadth of God's so-called "omniscience" (a word not found in the Scriptures). As one of His attributes, one would think that Christian theologians have thoroughly studied the Word of God and analyzed to death every text relevant to this aspect of God's Being and Mind. Surely there can be no mistake. Surely God has full knowledge of all that has ever existed and will exist in the future from eternity past, before He created everything. This is the generally held view among Christians. When you couple that belief with the idea that God's "omnipotence" and origination of everything as the great Creator makes Him culpable and personally responsible for all of the evil and suffering in our world - it's very difficult to resolve these ideas with the representation of God in the Scriptures as a God of holiness and love.
The biggest problem in all of this is that the Scriptures do not, in fact, reveal God's knowledge as being infinite according to the "omniscience" concept at all. Quite the opposite in fact. From Genesis to Revelation, God indicates (and states outright) that He does NOT "know everything about everyone". That's a very difficult reality check for Christians and a bitter pill to swallow considering the teachings received in most "churches" from cradle to grave.
I'll just touch on a few texts and point out some things most Christians miss completely when reading God's Word. One of the most glaring examples of God's knowledge limitations in Genesis is found in chapter 18 where the God appeared in the form of three men and had lunch with Abraham and then informed him of their agenda and purpose in this visitation. "20 And the Lord said, Because the cry of Sodom and Gomorrah is great, and because their sin is very grievous; 21 I will go down now, and see whether they have done altogether according to the cry of it, which is come unto me; and if not, I will know." Note that God did NOT "foreknow" the nature and extent of the wickedness in these cities. The "cry of it" came to him via angelic surveillance reports most likely. God went down to the cities personally to investigate and inspect them to see whether or not the reports were accurate. He was not about to destroy them based on second-hand information. This is a fascinating glimpse into God's knowledge limitations. In fact, He reveals the timeline of His acquisition of knowledge even more specifically and clearly in Psalm 139, "O lord, thou hast searched me, and known me. 2 Thou knowest my downsitting and mine uprising, thou understandest my thought afar off. 3 Thou compassest my path and my lying down, and art acquainted with all my ways. 4 For there is not a word in my tongue, but, lo, O Lord, thou knowest it altogether. 5 Thou hast beset me behind and before, and laid thine hand upon me. 6 Such knowledge is too wonderful for me; it is high, I cannot attain unto it." Note that David indicates comprehensive knowledge of him as a person by God based on "searching" him - a process of investigation. This would definitely not be necessary if God has full knowledge of everyone and everything that would ever exist from eternity past. Later in the chapter David writes (under the Holy Spirit's guidance and inspiration), "23 Search me, O God, and know my heart: try me, and know my thoughts: 24 And see if there be any wicked way in me, and lead me in the way everlasting." God would NOT have to "search" him out to determine the thoughts and intents of his heart if He had "omniscient" knowledge of David from eternity past. Obviously, this latter scenario is NOT the true nature of God's knowledge. God's knowledge is actively growing and developing continuously as people and circumstances change. It is dynamic and He is involved in discovery WITH His people.
Back in Genesis, this "searching" process is confirmed in the proposed sacrifice of Isaac by Abraham on an altar. His hand was withheld from killing his own son at the last moment in these terms, "11 And the angel of the Lord called unto him out of heaven, and said, Abraham, Abraham: and he said, Here am I. 12 And he said, Lay not thine hand upon the lad, neither do thou any thing unto him: for now I know that thou fearest God, seeing thou hast not withheld thy son, thine only son from me." Prior to Abraham's obedience in relation to this horrible requirement and sacrifice, God was unsure of the level of His trust and faith in Him and obedience to Him. This test set all questions in that area to rest for God. This test proved that Abraham was completely committed to God and to obedience to Him above all else. God's knowledge expanded and updated according to these new facts and revealed realities.
There is much much more in God's Word on this subject and in every case, God repeatedly confirms that He does NOT have full, comprehensive knowledge of each and every individual on this planet at any given point in history. He goes out of His way to carefully investigate His personal friends and People and gain very thorough knowledge of that very select group. Beyond that, He has general knowledge of what is going on among the rest of humanity and how that may affect His People, but He does not have infinite knowledge of all details. His all-encompassing knowledge is limited to the functions and details involved with sustaining and maintaining this reality and physical realm.
I trust these insights will be helpful to many seekers after Truth here.