Well, you and I will have to disagree on that in some small respects.
I think He does know us. He knew us in the womb, and He knows us out of it.
He did not design this world as a way to sort out people. He created it so that He would have someone to love and to love Him back. Sin is a conflict that comes between Him and His children and breaks up the intimacy between us. It is like those times when a husband and wife get too busy to spend time together, their intimacy suffers. They may be able to sit in the same room together, but the emotional bond has suffered and their awareness of each other at that level is impaired.
God wants us to be in Him, FEEL His grace and love at all times. But He also knows that we are human, and that we wander off in thought, get focused on something we are doing (sinful or otherwise), that pull us out of conscious awareness of His love. If I am making supper and am not focused on Him I probably do not feel His Grace at that time. Most likely, what I feel is harried. Later, when things are calm again I can tune back in and get in touch with His grace again.
However, making supper does not tempt me to not seek Him again. *l* Therefore, for me it is not a sin. A sin, a temptation, is something that keeps you from seeking Him because it feels good and feels like maybe it can replace Him. (For one thing, at the time sins seem to require less work than living with Him, but they obviously have their downside.)
Reaching out to God is about grounding yourself, recharging yourself. We sleep to recharge our physical selves, we visit with God in order to recharge our spiritual selves.
People who do not know Him, who put things between themselves and Him, are already harming themselves. They have cut themselves off from One who loves them more than life itself. That's already quite a bit of punishment, in my esitmation, so that to throw them away for all eternity for not seeking Him out... well, it just seems petty to me. And I don't believe that God is petty.
What He is is compassion beyond all comprehension. He is there all the time, within us and without. All we have to do is tune Him in and recognize His presence...that warm fuzzy feeling, that moment of Grace, however you experience it, so that you can say "oh, you are God. I know you now too!"
As a parent, there is nothing more thrilling than the first time your baby calls you Mama or Dada... except if you lost that baby but he came back to you. (The Bible speaks on this, of course.
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All people are struggling to find "something" that fits in their hearts, that makes them feel right and safe. That something is God, whether or not they know it or acknowledge it. But He knows it. And He is watching their every step, like any anxious parent who watches their baby stumbling along in a dangerous area. And he is ready to catch them even if they do not yet Know Him. Because he is compassion to the nth degree, and He would not let His baby fall. (Yes, He gives us free will, in the same way parents let go of their child as they walk, but He remains close by to catch us when we need catching.)