God is knowledge; he is knowing; and he is being known. Since God has knowledge of his own essence, and since God is one, it follows that the essence of God is knowledge. And knowledge means that he knows himself, and is known by himself.
-Ibn Sina, "al-Risalat al-Arshiya"
From "366 Readings From Islam," Robert Van der Weyer. 2000. John Hunt Publishing, United Kingdom.