The subject of this article is to deal with different dimensions of one of the most fundamental mystical topics, that is, the unity of existence. Ibn Arabi, the father of Islamic mysticism, has studied this issue in most of his works and has explained this issue in his commentary on Fuss al-Hakem. The unity of existence has various foundations that can be explained and interpreted both in Ibn Arabi's Fuss al-Hakem and in Imam Khomeini's commentary on it. The author tries to clarify the twelve foundations of the unity of existence, and throughout the article he tries to explain the notes and footnotes of Imam Khomeini (pbuh) on the text of Fuss al-Hakem about the interpretation of the unity of existence and clarify the contents of the deceased.