Reason is indispensable for the Christian life because without understanding growth is impossible. God designed for us to be converted and conform to Christ through mind renewal. Romans 12:1-2 lays out the importance of the this process:
I appeal to you therefore, brothers, by the mercies of God, to present your bodies as a living sacrifice, holy and acceptable to God, which is your spiritual worship. Do not be conformed to this world, but be transformed by the renewal of your mind, that by testing you may discern what is the will of God, what is good and acceptable and perfect.
As God’s truth permeates our minds, it imparts objective facts and it impacts our subjective thought process. In other words, God’s truth should fashion what we think and how we think. It provides us with the truth that we need to inform our thinking and to shape our wisdom. For this reason, and many more, an unreasoned Christian life is a deficient Christian life—the mind must be engaged.
That being said, we must never allow reason to rise to the level of authority. What does this mean? J.I. Packer incisively explains:
But all its many varieties spring from a single principle, namely, that the final authority for my faith and life is the verdict of my reason, conscience, or religious sentiment as I examine Scripture “what an open mind”, and measure it by what I have learned from other sources, historical, philosophical, religious and scientific. What under these circumstances reason and conscience say, what I find that “I feel”, that God says. (Packer, Fundamentalism and the Word of God, 50)
This kind of elevation can take place when theologians convene to determine what the historical Jesus actually said in comparison with what the Bible says, or when an individual Christian subconsciously decides that despite all that the Bible says about the trustworthiness of God anxiety is the proper course of actions. In both highhanded and everyday ways, we are prone to elevate our sensibilities to a place of authority.
The elevation of reason to a place of authority is a rebellious act and a devastating strategy for living the Christian life. Your mind (i.e., the way you think about life in its specifics and generalities) is bound by the will of God, not the other way around. At some point you must submit your reasoning to God’s revelation. As Packer contends, “those who acknowledge the Lordship of Christ are bound to accept the principle of biblical authority” (Ibid., 68).
If you won’t submit your reason to the authority of Scripture, you are walking by sight not by faith. This will never work because the Christian life requires faith. In fact, faith is the whole point of Christian reasoning. As God engages your mind with truth through the ministry of the Spirit, He is providing you with the content of your faith. If you don’t know what you believe, you don’t believe it. Your reason is not an end, it is a means to a god-ordained end—comprehensive and submissive faith in the Lord Jesus Christ.
Reason is the servant, truth is the master, and faith is the goal.
Again, Packer’s perspective proves helpful:
Again, whether or not we call ourselves Liberal, we are all in fact inclined to subjectivism in out theology. God’s thoughts are not our thoughts, and the God-centered approach which the Bible makes to problems of life and thought is in the highest degree unnatural to the minds of sinful and self-centered men. It calls for a veritable Copernican revolution in our habits of thought, and is slowly and painfully learned. On the other hand, it is entirely natural for sinners to think of themselves as wise, not by reason of divine teaching, but through the independent exercise of their own judgment, and to try justify their fancied wisdom by adjusting what the Bible teaches to what they have already imbibed from other sources (“modern knowledge”). (Ibid., 70)
Slowly and, when necessary, painfully we must comprehensively submit our reason to the authority of the Bible.