The word omniscience is not, strictly speaking, a biblical term. The word itself is not found in the Bible. It is a philosophical/theological word that has come into wide usage because, like the word trinity, it correctly describes the biblical evidence. The word means to see or know all things. For God, if this doctrine is true, everything is eternally "present." I have recently been going through a box of old newspaper clippings from earlier years. To my astonishment, I had forgotten, not only many things that happened to me, but many of the people involved. Time dims our remembrance of much that has happened. God is not like that. He always knows what is past, present, and future, if he is omniscient.
Many theologians, past and present, perhaps the great majority of them, have either made a short affirmative statement that God is all-knowing, or they have treated the doctrine as a "given," something which is so obvious in the Scriptures as to be commonly received. I agree with that position.
However, down through the years, particularly in times when there was a greater tendency to reflect on the whole counsel of God than is often the case today, a number of theologians took pens in hand to set forth a systematic presentation of this and related truths. We will begin by examining the work of one of the best representatives of reformed theology, Francis Turretin.