CS Lewis cited by Martin Moynihan
From a memoir I sleep but my heart watcheth - in the collection We Remember CS Lewis edited by David Graham , 2001:
[A questioner]: "Well, what is God?"
That's a facer, one thought.
"God", said Lewis, "is self-subsistent being, cause of himself."
Lewis's definition is of the God of the Philosophers - a philosophical definition of God. Thus an inferred definition, a definition which could be made only by a trained intellectual, and only be understood by a trained intellectual.
Blaise Pascal in the appendix to Pensees, describing his religious experience as noted down and carried by him:
"God of Abraham, God of Isaac, God of Jacob - not of the philosophers and scholars."
Pascal's answer to the question of 'What is God' is therefore NOT to describe God in terms of a philosophical definition nor of His Properties; but to say God is He that is told-of in the Bible, He that is Father of our Lord and Saviour Jesus Christ - and also our Father - we being his children.
Pascal's answer is history, fact, story - explicitly not philosophy.
Lewis's answer was designed to be acceptable to, find common ground with, a non-Christian intellectual who already believed in the categories and methods of Classical Philosophy - but the cost was to build-into Christianity, from its very axiomatic definitional basis, a set of philosophical categories and assumptions which have nothing to do with actual revelation - nothing to do with the described experiences of the ancient Hebrew Prophets of the Old Testament and how they knew God; nor with the teachings and actions of Christ and the Apostles in the New Testament.
Pascal (himself one of the greatest of philosophers) was teaching that the proper answer to What is God is to refer to revelation, to our knowledge and understanding of the experiences and teachings of scripture and Christian authorities.
It is NOT to answer with philosophical definitions that 1. Beg all the most important questions and 2. Put God onto an intellectual plane incomprehensibly far above 99 percent of humans - past, present or future.