Angels are not omniscient. That is, they do not know all that is and will be. We believe this partly because they are finite, created beings and partly because the New Testament portrays them as desiring to look into things. And it speaks of things being “made known” to them.
For example, Peter says that the gospel contains “things into which angels long to look” (1 Peter 1:12). And Paul says that the church exists so that “the manifold wisdom of God might now be made known to the rulers and authorities in the heavenly places” (Ephesians 3:10).
Angels are also sinless and in that sense perfect. Therefore, unfallen angels still learn things. So it is possible to be perfect yet ignorant of some things. It is possible to be perfect and still enjoy learning.
That implies that when Hebrews 12:23 refers to the saints who have died as “the spirits of the righteous made perfect,” we should not conclude that these saints are omniscient. In fact, it would be right to conclude that they do not yet know all they will know, but will go on learning things about God and his universe forever.
At least I cannot think of any reason to think there will ever come a point in eternity when finite minds will have infinite knowledge.
This is very good news to me, because when I was a child one of my greatest fears was that heaven would be boring. There would be no surprises and no growth in knowledge with accompanying increase of joy.
My view of God was too small and my view of myself was too big. I misinterpreted, 1 Corinthians 13:12, “Now I know in part; then I shall know fully, even as I have been fully known.”
I thought: Well, we will know everything in a flash. We will know God the way he knows us, and there will be no more discovery after that. Now I see this as philosophically improbable, morally bigheaded, and exegetically mistaken.
What Paul means is not that I will know exhaustively the way God knows me, but rather I will know accurately the way God knows me. The point is not that I won’t have limits to what I know, but rather I won’t have mistakes in what I know.
God is infinite and therefore inexhaustible in the complexity of his glory. His created universe, as the Hubble telescope shows, is big. His thoughts toward us are countless. And his ways are beyond finding out.
Part of what makes “eternal life” satisfying (and not boring) forever is that it will take an eternity for perfect, finite creatures like us to know God fully. He is perfect and infinite. We will be perfect and finite. He will enjoy increasing revelation of himself, and we will enjoy increasing jubilation in him—forever.