What does "God is Eternal" mean?

Answer: Bismillah, praise be to Allah and may Allah raise the rank of our beloved Prophet Muhammad (صلى الله عليه وسلم)

That statment means God (Allah) has no beginning to His existence. He existed before the creations, before time and place.

Al-Bayhaqiyy and Ibnul-Jarud narrated with sahih chain that the Prophet, sallallahu ^alayhi wa sallam, said  “Kanallahu wa lam yakun shay’un ghayruh,” which means “Allah existed eternally and nothing other than Allah  existed with Him.” So Allah exists without a place.

The scholars of Islam said that it is obligatory upon every mukallaf to know 13 Attributes of Allah. Allah is attributed  with: Existence, Oneness, Eternity, Everlastingness, Non-neediness of others, Power, Will, Knowledge, Hearing,  Sight, Life, Speech, and Non-resemblance to the creation.

Allah: has no partner, is the creator of everything, does not need any of  his creations, and absolutely nothing resembles Allah. Allah is great, the six directions do not pertain Allah, He is not sitting on the throne, He does not reside in the  heavens or in places as jews say, whatever you imagine in your mind Allah is different from it.

Allah exists without  a place is the belief of all Muslims.