We can use logic as a tool without being a rationalist because logic itself finds its ontological basis in the nature of the Creator of all things. In term of its nature, a particular principle of human logic is valid if it reflects the Mind of God as revealed in Scripture. Logic thus has an ontological basis and is not to be reduced to a relative and cultural psychology.
Man was made in the image of God, and part of this image is his capacity for logical thought, which is simply thinking God’s thoughts after Him. While man’s understanding is finite, it is nevertheless true because it comes from the image of God within him. Thus 1 + 1 = 2 is true for both God and man with the main difference being that God understands it infinitely and man finitely.
A close study of Scripture reveals that logic is used to convey, clarify, and defend revealed truth because it finds its own validity in God’s nature. For example, the “law of non-contradiction” is rooted in the very Being of the God who cannot lie (Titus 1:2). When Paul said that God cannot both be God and a lying God at the same time, he was actually saying:
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The rule of logic which is called “the denial of the consequence” is used in such places as Galatians 5:18-21; 1 Corinthians 6:9-11; 2 Corinthians 5:17, etc. In such places, Paul did not hesitate to argue:
If someone is in union with Christ, then he will be a new creature.
If someone is not a new creature, then he is not in union with Christ.
The Apostle Paul had no problem whatsoever “reasoning” from the Scriptures (Acts 17:2; 18:4, 19, etc.). In all his writings, Paul constantly used logically valid forms of argumentation to demonstrate from the Old Testament that Jesus was the Messiah.
We must also remember that although human logic can tell us if the structure of an argument is valid, it cannot tell us if it is true. Indeed, an argument can be logically valid and materially false at the same time! Observe the following example.
The above argument is logically valid but false! While something that is true will always be logically valid, the converse is not the case.
The logic or Logos of God is Jesus Christ, the Second Person of the Trinity. As the personification of divine logic, Jesus is the servant of the Lord and He does not sit in judgment on Divine Truth but seeks to serve it with reverence and humility. This is the true role of human reason.
A brief excerpt from Exploring the Attributes of God by Robert Morey