When Christian and Jewish philosophers say that God exists necessarily, what they mean is that He is non-contingent. In other words, he depends on nothing else to exist. Nothing caused Him to come into being, for He has always existed.
Since everything else that we know of was caused by something else, it is hard for us to grasp this idea. This is why little children ask, “If God made everything, then who made God?” But there is a very good reason why Christian and Jewish philosophers say that God must have always existed.
It is because absolutely nothing can’t cause a thing. How could something that doesn’t exist cause anything? As Maria said in The Sound of Music, “Nothing comes from nothing. Nothing ever could.” Philosophers call this common-sense principle ex nihil, nihil fit: “out of nothing, nothing comes.”
The first cause, obviously, must have had no cause or it would not have been the first cause. It must have been someone or something that always existed. Since our universe and life show signs of having been created by an intelligence, this leads us to infer that this first cause must have been someone rather than something that was pre-existent.
So, it must be that God simply IS. This may be one reason why, when Moses asked God for His name, that the name God gave to Moses for Himself was Yahweh, meaning I AM.
We should be glad that God necessarily existed rather than nothing at all, because if that were not the case, we would not exist, since nothing else could have come into being. All that would exist, and all that there would ever be, is absolute nothingness.
