This legitimate question is often asked in a sneering manner by those who deny the existence of God. It is actually a very important question for which every true believer should have an answer.
The answer? God did not come from anything. God simply is. He is Necessary Being Who, by His very nature, exists. Rational man can say this, but he cannot fully comprehend it. Our material brains operate in the physical universe which consists of time, space, and matter.
But the God Who created the universe cannot be affected by time, space, nor matter. He is above and outside of these things. Our human minds cannot understand how this can be, but we are forced by reason to come to the conclusion that this must be.
Human reason is defined as the ability to know things and their causes. We know as a fact that everything on earth was caused by something else. Everything on earth is contingent upon something else. The clearest example of this is in human reproduction. There is no human being who simply exists by his very nature. He must receive his life from his parents. It would contrary to human reason to state otherwise.
But it is also contrary to human reason to state that this chain of causality could go back infinitely.
There must be an original–a first–cause that caused all other causes. And this first cause could not be affected by time, space, or matter; because that would imply these things caused the first cause. An unreasonable and illogical proposition.
The only logical conclusion man can come to is that there must necessarily exist a First Cause, Himself un-caused. Nothing caused God–He did not come from anything. Everything comes from Him, because He is the great, First Cause.
And that is worthy of adoration.
TomNaegeleBlogs 
I hear sometimes the argument, Which is first, the chicken or the egg? Did man create God of necessity? Did God create man for His own glory? Or, is there a God? I read written (Revelation 4:8-9) that the God of the Bible spoken of in time is he who was, is, and is to come. As also, he that liveth forever and ever. And, Almighty God. Puzzles many they seem to be to depict or detect through the cryptic written, spelled, or designed. But I prefer to think of a step at a time.
A simple exercise in human reason will show that mankind must have been created by God. None of us can create ourselves. We rely on another for our creation. But this cannot go back infinitely. Somewhere there has to be a beginning to the process. This beginning could only be a divine being who simply exists by His very nature. He cannot possibly rely on anyone or anything for His existence. This we know as God.
Now why did God create man? Certainly not of necessity, because this would ascribe to God some limitation or imperfection. Man absolutely depends upon God for every last thing down to his very existence, but God does not depend upon man for anything. He created us simply out of the goodness of His paternal heart because this is what goodness does–it diffuses itself.
The way to light is through darkness, not through light. Confuse-ed chasing of tails only ensues trying to find light in light. It is a fight, but it is worth every try.
I believe in the God of the Bible, I believe God is eternal with no beginning, and I believe that God is Spirit (John 4:24). But “what” is God? Not “who” is God, but “what is God? We know that God is omnipotent, omnipresent, omniscient and eternal. And whatever life form this is, Christ himself describes this form of life as “SPIRIT”. We know God is not made of matter because God created matter and God’s “body” (his SPIRIT) could not be composed from that which could only exist after God created it. But we also know that God’s SPIRIT is energetic (in the sense that it has infinite power, yet the SPIRIT is not made from the usual form of energy that scientists study. I am sure that in heaven, God will one day explain to us the “physical” properties of his form of life. But I am curious if anyone has any has any ideas about what may compose God’s universe-sized “body” (other than simply describing it as a SPIRIT. I think there isa possibility that God’s SPIRIT may actually be LIVING TIME, specifically, four-dimensional LIVING SPACETIME. I have concluded this for several reasons, but one of those reasons is that Christ said, “I am the BEGINNING and the END” (Revelation 22:13). Most of us conclude that Christ was merely saying, “I AM eternal.” but there is at least the possibility that Christ might have been saying, “I AM [literally] the BEGINNING and the END–the LIVING PAST and the LIVING FUTURE.
So, my question is, “WHAT is God’s body (his SPIRIT) composed of such that God would naturally be omnipotent, omniscient, omnipresent and eternal? And what do you think of the idea that God’s “body” might actually LIVING TIME, specifically four-dimensional LIVING SPACETIME? And what do you think of my interpretation of Revelation 22:13?
This is very interesting. I’m going to have to get back to you.
Interesting that WordPress is promoting an Abrahamist site with just 28 followers. Who created Huichilobos? Oh Jesus, that one? Roman Emperor Constantine, of course, he said it himself!
Haha I think that’s the first time I’ve ever been labeled as an Abrahamist. Also, what?
Glad to amuse you! 😉 Well, I have to simplify, with more than 100 variants of Islam, more Jewish and Christian sects than I can count, etc.
Roman Emperor Constantine described himself humbly as the “13th Apostle”, and is celebrated as a Saint by the Eastern Orthodox Church. I don’t know if that’s because he had his son Crispus executed, his second wife steamed, or his nephew assassinated… In any case Constantine decided what Christianism would be, at the Council of Nicaea, in 325 CE…
Oh, wow, that’s some interesting alternative history you’ve made up there! There’s only one Christianity just as there is only one Christ. He’s the one who declared His teachings, and Constantine didn’t have a thing to do with that.