1 Peter 3:15—Why does Peter command believers to reason about their faith when the Bible says elsewhere to simply believe?

Problem: Over and over again the Scriptures insist that one should simply believe in God (cf. John 3:16; Acts 16:31). Hebrews declares that “without faith it is impossible to please God” (Heb. 11:6). Paul contended that, “the world through wisdom did not know God” (1 Cor. 1:21). Yet Peter here instructs believers to “defend” and give a “reason” for their faith. Aren’t faith and reason opposed?

Solution: Faith and reason are not mutually exclusive. A person should not believe in something without first inquiring whether it is a worthy object of belief. For example, few people would undergo a serious medical operation by a totally unknown person whom they had no reason to believe was anything but a quack. Likewise, God does not call on us to exercise blind faith.

Since God is a God of reason (Isa. 1:18), and since He has made us rational creatures in His image (Gen. 1:27; Col. 3:10), He wants us to look before we leap. No rational person should step into an elevator without first looking to see if there is a floor. Likewise, God wants us to take a step of faith in the light of the evidence, but not a leap of faith into the dark.

The Bible is filled with exhortations to use our reason. Jesus commanded, “You shall love the Lord ... with all your mind” (Matt. 22:37, emphasis added in all quotes here). Paul added, “whatsoever things are true ... think on these things” (Phil. 4:8, kjv). Paul also “reasoned” with the Jews (Acts 17:17) and with the philosophers on Mars Hill (v. 22ff) winning many to Christ (v. 34). Bishops were instructed to be able “to refute those who contradict” (Titus 1:9, nasb). Paul declares that he was “appointed for the defense of the gospel” (Phil. 1:17). Jude urged us to “contend earnestly for the faith which was once for all delivered to the saints” (Jude 3). And Peter commanded, “be ready to give a defense to everyone who asks you a reason for the hope that is in you” (1 Peter 3:15).

There are two kinds of belief. Understanding the relation between them is a key to discerning the relation between faith and reason.

The devil believes that God exists, but He does not believe in God. Belief that is a matter of the mind knowing something based on the evidence human reason can see. Belief in God (or Christ), however, is a choice of the human will under the persuasion of the Holy Spirit. So belief that will never save anyone (cf. James 2:14–20)—only belief in Christ can do that. However, no rational person should ever believe in something, unless he first has evidence to believe that it is true. No sensible traveler gets into an airplane with a broken off wing. So, reason is valid as a basis for belief that, but is wrong to demand as a basis for belief in (cf. John 20:27–29).

This excerpt is from When Critics Ask: A Popular Handbook on Bible Difficulties (Wheaton, Ill.: Victor Books, 1992). © 2014 Norman Geisler and Thomas Howe. All rights reserved. Used by permission. Click here to purchase this book.