How do we know we will know ‘why’?

How do we know we will know ‘why’?
Recently I closed a sermon on disability, sorrow, suffering and the sovereignty of God with a prayer that included suggesting that a day will come when we will know God’s purpose in suffering and sorrow.
I had a very good question from that prayer: how do we know we will know?  I.E. why was I confident to pray there will be a day, 10 000 days from today, when we will know why suffering, sorrow and disability existed?  When God will explain it to us.
I’ll be honest that it was an instinctive prayer, spontaneous from the flow of the sermon.  But there are, I think, two biblical markers those instincts are based on.
Satisfied with what we know
First, that we will know in the sense of be satisfied and have no more questions about sorrow, suffering and disability.
There is knowing and there is knowing.  Rarely are we pursuing knowledge in the sense of complete, full, detailed, technical manual type understanding.  Rather we want to know to a point we are satisfied.  When I say ‘I know how our car engine works’ I don’t mean I can fashion and build that engine from scratch.  I don’t even mean I know how every element works.  I don’t even mean I know enough to service it.  My knowledge is deficient at all those levels.  But when I say ‘I know how the engine works’ I mean, the level of knowledge I have satisfies me and leaves me no longer haunted by questions or concerns about my car engine.
This to me seems to be the prime ‘knowing’ we pursue as humans, not least because our finite minds can handle so little data.  It is a knowing that is both intellectually and emotionally satisfying.  The ability to look back on sorrow and suffering as ‘light’ and ‘momentary’ (2 Corinthians 4:17) seems to assume a level of knowing ‘why’ that satisfies.  Without that satisfaction my reflection on sorrow even a million years distant from it will not be light – perhaps conflicted, or sorrowful, but not light.
Equally an eternity of ‘no more tears’ (Revelation 21:4) must include the tears and tensions of not knowing or comprehending have been satisfied.
Ever increasing capacities to know
Having said this, secondly, I think the Bible would allow us to entertain the idea that our knowing won’t just be this satisfying knowing, but actually include sufficient mental capacities to comprehend in a detailed, technical manual type manner the purpose of our suffering.  ‘To know fully even as I am known’ by God (1 Corinthians 13:12) seems to suggest our knowledge will be at least comparable to God’s.  The earlier context of 1 Corinthians 12 compares our present ‘knowledge’ as like a child’s and our eternal knowledge that of adulthood.  A ‘completeness’ of knowledge is coming (13:10).
And places like 2 Timothy 2:7 ‘Think upon such things and the Lord will give you understanding in them all’ are promises for today that presumably stretch and escalate into eternity and suggest a growing, ever-completing understanding of the purposes of God.
So I think biblically we can know we will know because:
First, we will have a knowledge that satisfies and removes the tension and confusion of why.

Second, we will have infinitely expanding capacities emotionally and mentally to know as God knows.  But don’t worry – God’s knowledge is infinite so be really thrilled with the prospect of eternity as an ever-expanding infinite place of knowledge and beauty and right and joy.  Sounds good.