What does it mean to know someone?
Even answering the question would assume at least a working definition of ‘knowledge’.
Vincent van Gogh (1889 Jun) - Starry NightAnswers might range between ‘knowing how that person would act in a given situation’, to ‘knowing facts about that person’, to ‘the length of association that we’ve had with that person’. All are within the range of what it means to ‘know’.
Before we can answer, ‘what does it mean to know someone‘, we need to answer the more basic question, ‘what does it mean to know‘.

But here’s where it gets a bit curly…
what we mean by know depends on what we are knowing. When I say, ‘I know Dave’, I mean something different to when I say, ‘I know the rules of Cricket’. The primary criteria for knowledge are drawn from the object known.
Does this sound circular to anyone?
How can you then know something until after you’ve known it? Or more precisely, I won’t know something, and then I will, and I will only know that I know when I know.
Ouch.

Ignore all that mucking about with words,
what matters is this:
What it means to have knowledge of God will be determined by who God is. We can’t take our definition of knowledge from another field of study and apply it here, thinking that when we’ve amassed enough facts or hours we will have obtained knowledge.
We can’t know what it means to know God until we know who he is.

this would be an impossibly circular situation, except that God is not the passive object of knowledge. He is the Divine Subject of Revelation. He is the God who reveals:

“The king said to Daniel, “Your God is indeed God of gods, Lord of kings, and a revealer of mysteries”” (Dan 2:47 HCSB)

The first great act of God’s revelation of himself was in creating us. We are the receptacles of divine revelation.

When ever I soak up the starlight at night I’m amazed to think that out of all the length of creation that is known to humanity, we alone possess consciousness. We alone are aware of the universe and ourselves within it. That consciousness is not merely for marvelling at stars, it was brought into being to marvel at the Creator.

God’s first act of revelation to us was in creating us as beings capable of comprehending his divine disclosure.

Knowledge of God is not utterly beyond us, because he created us for himself. Calvin’s Geneva Catechism begins:
‘What is the chief end of human life? To know God by whom men were created.’
This is not primarily a claim about what people should do with their lives. It is a claim about what God has done in creating us. He has made Us as His.

Whose primary function and greatest good is knowing him.