I have been asked a lot of questions over the years, but believe it or
not, no one has ever asked me this question! Without context, I am not
sure exactly what question you are asking. I would assume you are asking
one of the following two questions:

1) What is the philosophical/theological definition of the monotheistic
God?

or

2. Who is the God of the Bible?

Let me take a stab at answering both questions.

From a philosophical/theological point of view, God has been defined in a
few ways. First, one could mention the teleological definition. Teleology
has to do with cause. It is a law of the universe that everything which
happens has a cause. Even those who are not trained in philosophy or logic
would concede, if they thought about it long enough, that everything which
happens is caused by something, even if we do not know the cause. By this
logic, one is inevitablely led to the question what was the initial cause
behind the universe itself? Given that the nature of the universe, that
everything has a cause, then God, by definition, is the required uncaused
cause of the universe. To the average person who does not spend a lot of
time thinking about philosophy, this may seem like a very unsatisfactory
definition of God, but if one thinks long enough about the teleological
definition, although it tells us very little in detail about God–it
certainly does not lead one to the God of the Bible–it really is a
compelling argument that God exists.

Another philosophical definition of God is that God is the designer of the
universe. Some people (atheists in particular) would claim that the entire
physical world can be explained by assuming that random processes are at
work. Far more reasonable, given the existence of life and its massive
complexity and given the fact that the laws of nature seem to be
fine-tuned to allow for life, is to accept that nature implies a designer.
Scientific investigation has proved to us that nature follows highly
predictable and invariant laws. This fact seems to imply a single designer
for the world (ie. science implies monotheism rather than polytheism).
This designer, is, by definition, God. If we use design to define God, we
learn a bit more about God than we do from the teleological argument. God
has a definite purpose and plan according to the design definition.

Other philosophical definitions of God have been proposed, including the
ontological, which says that the mere fact that we can conceive of God
implies that he exists. I personally do not find this definition either
compelling or useful. Again, other philosophical definitions of God exist,
but let us move on to the second area of defining who God is. Who is God
according to the Bible? This may not be quite as simple an endeavor as it
seems at first glance. God is defined in a number of ways in the Bible.
Let us start with the one time in the Bible in which someone asked God to,
in essence, define himself. In Exodus 3:11-15, Moses asked God who he
should say had sent him. God replied that he should tell them I AM has
sent me to you.” By this definition, God is the ever-present, uncreated
being. This sounds remarkably like the teleological definition!

Let us consider a couple more biblical definitions of God. I like the
definition given in Job 38-41. “Where were you when I laid the earth’s
foundation… Who marked off its dimensions…Who shut up the sea… etc.
Here, God is defining himself to Job and Elihu as the creator of the
universe. This sounds a lot like the design argument/definition of God.
Another definition is that given in 1 John 4:8. “God is love.” This is
truly a different definition for God. Many other definitions of God could
be given and substantiated by scripture. God is the Judge, God is the
Provider,… To summarize, according to the Bible, God is the
ever-present, all-powerful, loving Judge of the world.

I am not sure which definition of God you were looking for, but hope that
this reply has been at least a bit helpful.

John Oakes, PhD