Something to meditate on.
Not "what" but who is God? Since God created man in His image we know He is a personal (relational) God since we are relational beings.
God is perfect existence.
God the Son, Jesus, is perfect expression of perfect existence.
God the Holy Spirit is perfect appreciation (i.e.perfect knowledge) of perfect expression of perfect existence.
The Trinity - three in one and one in three.
And all expressed in the first few verses of Genesis.
"In the beginning, God…" perfect existence.
"And God said, let there be light and there was light…" Perfect expression of perfect existence.
"And God saw the light that it was good." Pefect appreciation of perfect expression of perfect existence.