How was God created or how long has he existed? What does “I am what I am” mean?
This is one of the classic questions, both of skeptics of Christianity, but also from some believers. It is a response to what is known as the cosmological argument, which goes like this:
Premise: All things which begin to exits are caused.
Premise: The universe began to exist.
Conclusion: The universe was caused and that cause, by definition, is God.
This seems to be a really solid line of reasoning. Philosophers debate such things, but no one has ever proposed anything which began to exist which was not caused (although ultimate skeptic philosopher David Hume argued against cause and effect entirely). In addition, science has made it clear that the universe has a beginning. These being true, then it it appears the conclusion that a Creator/God exists seems to be established by the Kalaam Cosmological Argument.
However it begs the question: OK, but who caused God? If God is Creator, then who created God? This is a natural question to ask, and we cannot blame the atheist (or the believer for that matter) for asking.
You may not be fully satisfied, logically, at the answer I am about to give, but there really is only one answer that fits all the information. The answer is that God, by definition, is the Uncaused Cause. God is the self-existent one, who literally did not begin to exist. God expresses this to Moses when he spoke from the burning bush. Moses asked God, “Who should I say sent me?” In Exodus 3:14, God replied to Moses, “I AM that I AM” “Tell them that I AM has sent me to you.” This is the tetragrammaton name for God YHWH. Some say Jehovah, which is not a terrifically good approximation of the Hebrew. Closer pronunciation of YHWH is Yaweh. In naming himself Yaweh, God tells us something about himself. He says I AM! In other words, I am the self-existent, eternal one. I had no beginning, and I have no end. I simply AM. Jesus took this name on himself in John 8:58, in a response to Jews questioning his authority, Jesus said of himself, “Before Abraham was born, I AM.” He did not say before Abraham was born, I was. No, he said I AM. Here, Jesus takes on himself the name YHWH, and claims to be the self-existent, uncreated God. Not surprisingly, some of the Jews decided to kill him at that point!
The conclusion, then, is that God was not created and, believe it or not, asking “how long” he has existed is a nonsense question. God simply IS. In fact, if we take the scientists to be correct on the big bang and the creation of the universe, before the universe was created, there was no time at all. Time itself began at the creation event. Asking what existed “before” the creation event is, again, a nonsense question. Time literally has a beginning, but God exists outside of time. He IS.