Imam Abu Ja^far at-Tahawiyy who died 322 A.H. said: "Allah is clear of boundaries, extremes, sides, organs and instruments. The six directions do not contain Him unlike the case of all the created things ".
http://alsunna.org/tahawi.htm
Allah said in Surat Ibrahim verse 10 { أفى الله شك }
which means: There is no doubt about the Existence of Allah.
The existence of this world is a proof for the existence of Allah. It is intellectually invalid to accept the existence of an action without someone doing it as it is invalid to accept the existence of copying and writing without a copier and writer. Hence, this world by precedence has a Creator and this Creator is Allah the exalted.
Allah exists and is not similar to existing things. He exists without a manner of being and without place. Imam Ahmad ar-Rifa^iyy, said: "The ultimate knowledge about Allah is to believe with certitude in his Existence ta^ala without a manner of being and place."