In answer to the question: "God came from where?" The simple answer is that God didn't 'come' from anywhere. Why? Because God is the Supreme Mystery of what is the very 'substance', 'stuff' and essence of what timeless, uncreated existence itself is. He simply is. He is of Himself, unto Himself. Scripturally, He says of Himself, "I am, who am." "I am He who is." (Exodus 3:14) "I am the first and I am the last, and besides me there is no God." (Isaiah 44:6) And to mankind He says, saying to His prophet Jeremiah. "Before I formed you in the womb, I knew you." (Jeremiah 1:4) In this, is conveyed the sense of His power and of the timeless ever-presence of His eternal being.
We must remember that if there was not always 'something' existing, then still now there would be no existence whatsoever. From absolute nothingness, no created existences, which we and the whole creation are, could ever have been generated.
Time is a dimension which unfolds for the whole of creation and all of its creatures. It does not apply to the Creator. God's millennial creative act has occurred, and is still occurring, within the timeless ever-presence of His own eternity. Within His timeless ever-presence He is present to, and sees its whole millennial entirety as one complete picture from start to finish. This is what enables Him to intervene at will, as He has in the course of history, giving of his foreknowledge to his prophets to benefit the lives of His creatures. There are no surprises for Him.
"He sees all that every human being does. There is no way to hide from His sight. He sees the whole of time, from beginning to end, and nothing takes Him by surprise." (Sirach 39:19-20 and Ecclesiasticus 39:24-25.)
Everything which has come into existence by His creative gift, is given to share in, and to partake of, something of the wonder of His own Existent Being. Scripture confirms, "It is in Him that we live and move and have our being." (Acts 17:28) And this is how we know our every prayer is heard, and how it is that every heart is known to Him, because we are in Him, and He is thereby necessarily present and witness to our every thought, word and deed. We are all transparent before Him within the unfathomable mystery of His eternal essence.
With regard to 'Space'; it too is created and exists within the mind of God. And as 'Mind' knows no boundaries, so too 'Space' is limitless within His limitless essence and mind.
"O God, Where could I go to escape Your Spirit? Where could I flee from Your Presence? If I climb the heavens You are there...." (Psalm 139:7-8)
Being the very substance, nature and essence of what is existence itself, His existence is the absolute supreme mystery. It is beyond explanation. We can come to 'see' how it works, but the creature cannot explain the 'why' or the 'how' of what is an Infinite Ever-Presence. We can only gasp and proclaim the awesome wonder of the reality of its Being, as we, as totally dependent beings without self-sufficiency are taken along the sure path to that which is the necessary Origin of all creatures, to the Ultimate Being which is necessarily not created and not dependent, but which is eternally, totally self-sufficient; the Being upon which all dependent beings depend for their existence. The relationship of a person with his or her Creator is deep, personal and profound.
Unending thanks, praise and glory be to our Father-Creator and God forever.