He is Allah, other than whom there is no deity, Knower of the unseen and the witnessed. He is the Entirely Merciful, the Especially Merciful.
Sufis believe in the existence of a single, personal God, Creator and Preserver of the universe, both transcendent and immanent to it. Does the Qur’an not say:
We are closer to him [man] than his jugular (neck) vein[Qāf50:16]:
but also; No human vision can encompass Him whereas He encompasses all human vision [Al-‘An`ām 6:103] 
and; Never can you see Me![Al-‘A`rāf 7:143]
What Muslims dare to say about God-whom they call ‘Allah’ (as Arabic Christians do )- is absolutely limited to what Allah overtime revealed about Himself. In the Qur’an can be found plenty of ‘’Allah’s most beautiful names’’ (al-asma al-husna) which must be understood as Allah’s attributes of perfection. Examples are al-wadud (Lover: Loved One) and al-muntaqim (Revenger).
These attributes obviously relate to each other in a dialectical manner and therefore seem to be contradictory while being compatible: this is the only way of that least vaguely indicating some of Allah’s majestic being. Surat Al-Ĥashr 59:22-24 offers the broadest list of divine properties:
He is Allah, other than whom there is no deity, Knower of the unseen and the witnessed. He is the Entirely Merciful, the Especially Merciful.
He is Allah, other than whom there is no deity, the Sovereign, the Pure, the Perfection, the Bestower of Faith, the Overseer, the Exalted in Might, the Compeller, the Superior. Exalted is Allah above whatever they associate with Him.
He is Allah, the Creator, the Inventor, the Fashioner; to Him belong the best names. Whatever is in the heavens and earth is exalting Him. And He is the Exalted in Might, the Wise.
There are sundry anonymous lists of Allah’s most beautiful names, all registering exactly 99 such attributes found in Qur’an and Sunnah. Beautifully calligraphed one can find the most traditional of these catalogues is many Muslims homes as wall decorations.
Allah’s secret 100th name is missing: a way of recalling that all human attempts to seize Allah’s ultimate reality are futile.
Ar-Rahman and ar-Rahim are the very attributes of Allah most frequently mentioned in the Qur’an. This assures man that Allah, both in principle and action, is quintessentially compassionate and gracious; in fact Allah is seen as having prescribed for Himself mercy [Al-‘An`ām 6:12,54].
Indeed, except for the 9th Sura (dealing with warfare) all other Surahs open with the so-called basmala: In the name of Allah, the Compassionate, the Merciful! (bismi-llahi-r-rahmani-r-rahim). With this formula-or at least by saying ‘’bismillah!’’ Muslims start any activity, whether they are about to drink a gulp of water or to insert the car key into its lock.
