While it is true that the word 'omniscient' does not occur in the bible, I think it is nonetheless a biblical concept (just like the word 'trinity' does not appear in the bible either). At some point I will write a full article about this, but for the moment, here's a few biblical passages that would appear to support God being omniscient. Bear in mind that this is by no means complete, and I haven't yet had a chance to order and explain them as much as I would like.
- Elihu describes God as the one "who is perfect in knowledge" (Job 37:16 c.f. Job 36:4)
- John says that "For God is greater than our heats and he knows everything." (1 Jn 3:20)
- The writer of Hebrews says that "Nothing in all creation is hidden from God's sight. Everything is uncovered and laid before the eyes of him to whom we must give account." (Heb 4:13 c.f. 2 Ch 16:9)
- Job said "for he views the ends of the earth and sees everything under the heavens" (Job 28:24).
- Jesus said "Are not two sparrows sold for a penny? Yet not one of them will fall to the ground apart from the will of your Father. And even the very hairs of your head are all numbered." (Mt 10:29-30)
- God said to Isaiah "for I am God, and there is no other; I am God, and there is no one like me, declaring the end from the beginning and from ancient times things not yet done" (Is 46:9-10 c.f. Is 42:8-9)
- Psalm 139 - all of it, but in particular: "How precious to me are your thoughts, O God! How vast is the sum of them! Were I to count them, they would outnumber the grains of sand." (vv. 17-18) "All the days ordainded for me were written in your book before one of them came to be." (v. 16)
But to briefly summarise, I think there are a number of verses that directly point to God being omniscient. In addition, reason would appear to indicate that if God is the most perfect being (as Christianity and the bible would appear to attest), then it makes sense that he is also perfect in knowledge, and hence omniscient.


Comments
Thanks Dave, much appreciated! Those scriptures seem to speak for themselves!
These scriptures "seem to" speak for themselves, but on second thoughts they certainly don't imply God's comprehensive foreknowledge of all definitive future events. God the risk-taker still remains!I have made a new post on my blog to this effect.
No, I deliberately left out those ones for now as I was trying to show omniscience, not foreknowledge. There are about four categories of views about God's foreknowledge amoung Christians: Open Theism, Simple Foreknowledge, Middle Foreknowledge, and full predestination. I will blog in more detail about those when I get a chance - probably early next week.
I have now posted my article on predestination which does look at some of those scriptures that do imply God's foreknowledge. I intend to add to this in the near future and write an article specifically discussing open theism.
If God is omniscient, why are there places in the Bible like Genesis where God is surprised? Or if God is everywhere at once, why did he leave the Garden Of Eden and then come back to be surprised by Eve and the snake?