Some time ago, I remember a believer asking me to help them answer a question from a child. The child had asked, “How do we know God exists?” In preparation for an upcoming class, I’ve been reading the various arguments for God’s existence. There are almost an infinite number of arguments advanced to make the case for the existence of God, but most have recognized that, historically speaking, the arguments for God’s existence fall into roughly one of six different arguments (cosmological, teleological, ontological, moral, universal consent, and historical-theological).

In the glossary of his Systematic Theology: An Introduction to Biblical Doctrine, Wayne Grudem provides incredibly helpful and brief definitions for a few of these arguments. Here is what Grudem says about the first four: The cosmological argument is an “argument for the existence of God based on the observation that, since every known thing in the universe has a cause, the universe itself must also have a cause, which can only be God” (p.1238). The teleological argument is an “argument for the existence of God which reasons that, since the universe exhibits evidence of order and design, there must be an intelligent and purposeful God who created it to function in this way” (p.1255). The ontological is an “argument for the existence of God that begins with the idea of God as the greatest of beings that can be imagined. As such, the characteristic of existence must belong to such a being, since it is greater to exist than not to exist” (p.1249-1250). The moral is an “argument for the existence of God which reasons that there must be a God who is the source of man’s sense of right and wrong” (p.1248).

Herman Bavinck in his Reformed Dogmatics, Vol.2: God and Creation helpfully defines the final two arguments in the following way: The universal consent is an argument for the existence of God which reasons that since “there are no peoples on earth without religion,” nor have there ever been, that the universal consent or inclination of humanity in this regard displays the existence of God. From universal consent we learn that “religion is not an individual or particularistic but a universal phenomenon rooted in human nature itself” (p.87-88). Finally the historical-theological argument is based “either on the facts that historians unearth or on the idea from which, consciously or unconsciously, their view and study of history proceed.” Scholars take their evidence and notice that “there is a momentum in history, that an idea and a plan are being realized, that a goal is being pursued,” and that all of this “points back to a wise and omnipotent World-Ruler” (p.88).

For a more comprehensive explanation of these arguments and an evaluation of them, let me encourage you to read more about them in Herman Bavinck’s Reformed Dogmatics, Vol.2: God and Creation. In sum, Bavinck concludes that they are all helpful, but that they don’t actually prove what they set out to prove. Rather, together these “proofs” powerfully testify to the truth that God exists. And I think he is right. Do not fear. God exists. Only a fool says in his heart there is no God (Psalm 14:1).

So how do we answer that question, “How do we know that God exists?” Well, I’ve often answered it in the words of the Baptist Catechism of 1813, “The light of nature in man and the works of God plainly declare there is a God; but his Word and Spirit only do it fully and effectually for the salvation of sinners.”

We may and should point our children, family, and friends to the evidence that God presents to us in creation (see Rom. 1:19-20), but O how we need the Word and Spirit of God (1 Cor. 2:10; 2 Tim. 3:15-16)! We need God’s Word and Spirit in order to truly understand and believe not just that God exists, but that a personal, holy, and gracious God exists. It is helpful to take our friends to the evidence that the creation presents, to show them how the heavens declare the glory of God, and to have their consciences cry out to them as they look at the wonder of the creation, but we must take our friends and family to the Bible if they are to ever come to true and saving faith in Jesus. And if we ever needed a good reason to study the Bible here is one – it is only in the Bible that we truly come to know who God is, what he has done, and how we might know him, love him, glorify him, and enjoy him for all eternity. For it is not enough to know that a God exists, we need to know that God, and know him personally. So let’s pick up and open our Bibles each day with joy, knowing that we have the privilege of learning about our great and gracious God.