Shorter Catechism Q. 4. What is God? A. God is a spirit, infinite, eternal, and unchangeable, in his being, wisdom, power, holiness, justice, goodness and truth.
Commentary: A.A. Hodge said that this is the best definition of God ever written. Although that might be excused as a bit of hyperbole from a biased Confessional Presbyterian who was reared on the Shorter Catechism, it must be admitted that it is a good answer to a difficult question. It is not an exhaustive description of God, and it is not a perfect one. Indeed, it has been faulted for not including love in its answer, especially when the Bible explicitly says that God is love. To be fair to the authors of the catechism, they probably would have responded to this criticism by noting that love, along with grace, mercy, kindness, etc., are subsumed under the term “goodness.”
God is a spirit, which means that he is an immaterial being. That which is immaterial cannot be seen or touched or weighed on a scale. In other words, God does not have a body like we do (Children’s Catechism #9). We have a spirit or an immaterial aspect, which is the part of our being where we think, love, choose, and so on. If a surgeon were to operate on our brain, he would not be able to see our thoughts or decisions because our spirit is immaterial and cannot be seen by the naked eye or by a microscope. Even though our spirit is in some ways like God who is Spirit, we must understand that God is holy and wholly distinct from us. He is the Creator, and we are his creature. His being is different from any created being. God is not simply a bigger version of ourselves or of angels. He alone is God and there is no one like him.
God is infinite, that is, he is unlimited in his being and in all his attributes. He is everywhere, all-knowing, all-wise, and all-powerful. He is thrice holy, full of justice, goodness and truth.
God is eternal. He has no beginning and no end. Indeed, he created time and exists outside of it. God is unchangeable. He doesn’t grow in wisdom or become more loving over time. He is the same perfect God yesterday, today and forever.