In the end, God is holy in that he is God and not man. . . . He is incomparable. His holiness is his utterly unique divine essence. It determines all that he is and does and is determined by no one.Read the rest.
His holiness is what he is as God which no one else is or ever will be. Call it his majesty, his divinity, his greatness, his value as the pearl of great price.
In the end, language runs out. In the word “holy,” we have sailed to the world's end in the utter silence of reverence and wonder and awe. There may yet be more to know of God, but that will be beyond words.