Gospel Guidebook: Getting and Keeping It Right 
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Believe or Trust?
by Robert P. TerryUpdated July 18, 2025
When it comes to the Bible, many people seem to have the impression that the English words believe and trust mean the same thing, even though they don't. In fact, these English words represent different words in Greek New Testament. In salvific passages, the word believe is the word that is used exclusively (100% of the time) in the New Testament. For example, in the the Gospel of John, inflections of the infinitive "to believe" (πιστεύειν) occur nearly 100 times (dozens of which are salvific), while inflections of the infinitive "to trust" (πείθειν or ελπίζειν) occur only one time in a passage that is not salvific. Now, I understand that in English "to trust" can be construed to mean "to believe," but it can also (and most often) be construed to mean a lot of other things, too. "To believe" refers to intellectual assent to a proposition, whereas in theological circles, "to trust" (Latin, fiducia) has somewhat of an elusive and mystical meaning to it. It can mean "to rely on," "to commit," "to surrender to," or "to pledge allegiance to" depending on whom you ask. And what is even worse, the Greek words that can be translated as "to trust" (πείθειν or ελπίζειν) don't mean most of these things. The Greek word πείθειν most commonly means "to rely on," "to be persuaded of," "to be convinced of," and "to be confident in," and the Greek word ελπίζειν means "to hope." But for the theologians who insist on fiducia, the word is elusive because it supposedly entails the mystical working of the Holy Spirit in the heart by which the sinner "appropriates" to himself the merits of Christ. For example, Louis Berkhof in his famous Systematic Theology explains "saving faith" as follows: "When the Bible speaks of faith, it generally refers to faith as an activity of man, though born of the work of the Holy Spirit. Saving faith may be defined as a certain conviction, wrought in the heart by the Holy Spirit, as to the truth of the gospel, and a hearty reliance (trust) on the promises of God in Christ" (p. 503; italics his). And as for the elements of this faith, fiducia "is the crowning element of faith," and it "consists in a personal trust in Christ as Saviour and Lord, including a surrender of the soul as guilty and defiled to Christ, and a reception and appropriation of Christ as the source of pardon and of spiritual life" (p. 505). So, fiducia is a "hearty reliance (trust)" that includes a lot of things, such as surrendering one's guilty soul and receiving and appropriating Christ (all of which are ascribed, of course, to the working of the Holy Spirit in the heart in order to obfuscate the insidiousness of teaching salvation by works). It is for reasons like these that the English word trust should be avoided when describing salvific passages in the New Testament.