He is Jehovah. God is most high in the sense that He is far above us in glory. There is nothing that can be compared to God or likened unto Him. He is the most high, He is holy. He is above human knowledge.
Man is but a little child in knowledge.
God's knowledge is most high. He knows all things and knows all things at the very same moment. He is above all needs and wants. He never longs and is never dissatisfied. He is never one who lacks.