SIFAT ...  HAZRAT INAYAT KHAN explains:

In the terms of the Sufis the Self of God is called Zat, and His qualities, His merits, are named Sifat. The Hindus call the former aspect of God Purusha and the latter Prakriti, which can be rendered in English by the words spirit and nature. Zat, the Spirit of God, is incomprehensible. The reason is:  That which comprehends Itself is Intelligence, God's real Being; so comprehension has nothing to comprehend in its own Being.

No doubt, in our usual terms it is the comprehending faculty in us which we call comprehension; but in this it is not meant so, for intelligence is not necessarily intellect.

he further explains:

Islam believed in One Only God with many attributes, and yet beyond any attributes; invisible, and beyond the comprehension of man; Almighty; Incomparable; no one save He having any power beside Him; the Knower of all things, and pure from all impurities; free from all things, and yet not far from all things; in Him all abiding, and He living in all. The whole essential teaching of Islam ( which is called Kakamat ) tends to explain clearly the oneness of God; and yet the attributes are suggested, not in order to explain God, but with a view to make God intelligible to the human mind.

These attributes form the external part of God, which is intelligible to man, which is named Sifat; but that which is hidden under attributes, and that which cannot be intelligible to the human mind, that part of the Divine Being is the real Being, and that Being is called Zat. The whole tendency of Islam has been to disentangle man's heart from such thoughts of God as limit and divide Him, and to clear man's heart from duality, which is the nature of this illusory world, and to bring him to that atonement with God which has been the real aim and intention of every religion.