Scripture portrays human response to God as engaging the whole person, not just isolated intellectual agreement. The brain processes through different modes—understanding, trusting, choosing. The New Testament gives these modes names: mind (nous), heart (kardia), and various expressions of willing and choosing—to describe how a person hears, understands, trusts, and obeys God. These are not separate selves or independent agents, but distinct aspects of one person responding to God—aspects of the unified response to the Gospel that Paul calls “the obedience of faith” (hypakoē pisteōs) (Romans 1:5; 16:26). 1,2,3,4
Scripture explicitly identifies the mind (nous) and heart (kardia) as distinct terms for different aspects of human engagement with God. While the New Testament doesn’t use a single noun for “the will” as a parallel term, it consistently describes willing, choosing, and acting as functions distinguishable from both mental perception and heart-level trust. For clarity, this appendix uses “the will” to refer to this choosing and acting dimension of human response.
Overview of Human Response
- Mind: understanding the gospel message (intellectual grasp and discernment).1,2
- Heart: trust, desire, and moral direction to Christ (personal entrustment).1,2
- Will: concrete choice and obedience (personal surrender).
The Mind (Nous)
The mind represents the mode by which a person perceives, understands, and makes judgments about the truth of the gospel.5
Scriptural emphasis: Paul speaks of being “transformed by the renewal of your mind” (nous) (Romans 12:2), warns that “the god of this world has blinded the minds of the unbelievers” (2 Corinthians 4:4), and describes unbelieving minds as darkened and alienated from the life of God (Ephesians 4:18; Titus 1:15).2
Lexical note: The major lexicons gloss nous as mind, intellect, understanding—the mode by which a person thinks and perceives.5 That is the lexical base for this book’s use of “mind.” The moral and spiritual weight the word carries in Paul comes from the passages surveyed above, where the mind is renewed, blinded, or darkened.
The mind can accurately recognize truth without yielding to it. A person may understand and even assent to the gospel cognitively while remaining unchanged in posture toward God.1,2
The Heart (Kardia)
The heart represents the mode encompassing trust, desire, and moral direction.5
Scriptural emphasis: “With the heart one believes and is justified” (Romans 10:10), and “where your treasure is, there your heart will be also” (Matthew 6:21), locating trust and moral direction in the heart.2 The warning “harden not your hearts” (Hebrews 3:8) and the Lord’s opening of Lydia’s heart to respond to Paul (Acts 16:14) further show the heart as the site of receptive or resistant response to God.2
Lexical note: Kardia is defined as the inner core of a person, including volition, emotion, and moral evaluation—not merely feeling, but the deep center of commitment. Though kardia’s range includes volitional elements, the New Testament’s own verbal vocabulary (thelō, boulomai) treats choosing as distinct from trusting, and this appendix follows that distinction (see The Will below).5
When the heart entrusts itself to Christ, the will has a choice to make.
The Will (Thelō and Related Terms)
“The will” as used in this appendix refers to the aspect of human response involving both choice and action based on what the heart desires. This usage is derived from the New Testament’s verbal and contextual presentation rather than from a single Greek word.1,2 The will first chooses in repentance (metanoeō)—surrendering control, abdicating the throne—and then executes the turn (epistrephō)—changing direction from sin toward Christ. That turn produces visible, ongoing fruit (erga), demonstrating what the new direction looks like in a lived life and giving concrete form to the heart’s allegiance (Acts 26:20).
The New Testament clearly speaks of willing and choosing but doesn’t employ a single noun for “the will” as a term parallel to mind (nous) and heart (kardia).5 Instead, will-language is expressed chiefly through verbs such as thelō (“I will, I want, I desire”) and boulomai (“I intend, I resolve”), and through the noun thelēma (“will,” as in “God’s will” in Romans 12:2).5
Scriptural emphasis: Paul’s inner conflict in Romans 7 uses thelō and related forms to distinguish between what he “wants” to do and what he actually does (Romans 7:15–19), showing a tension between approving God’s law “in the inner being” and failing to carry it out in action (Romans 7:22–23).3 Jesus’ prayer “not my will (thelēma) but yours be done” (Luke 22:42) and the disciples’ submission, “the Lord’s will be done” (Acts 21:14), demonstrate human willing set in relation to God’s will.
Lexical note:
- thelō / thelein: to will, desire, have in mind, express a preference or intention.5
- thelēma: (1) the act or authority of willing (will); (2) what is willed, that is, a decision or intention; often used of God’s will (e.g., Romans 12:2).5
- boulomai: to intend, decide, resolve after deliberation.5
Coordination in Conversion
Conversion engages the whole person—mind, heart, will, speech, and body—in a unified response to the gospel.3,4
- Mind: hears and understands the message. “Faith comes by hearing” (Romans 10:17).2
- Heart: entrusts itself to Christ. “With the heart one believes” (Romans 10:10).2
- Will: chooses to turn in repentance and then executes the turn. “Repent (metanoeō) therefore, and turn back (epistrephō) that your sins may be blotted out” (Acts 3:19). 4
- Mouth: confesses allegiance. “With the mouth one confesses and is saved” (Romans 10:10).2
- Body: is baptized into Christ. Buried with him, raised to walk in newness of life (Romans 6:4).5
These aspects work together as one unified response. A heart that has genuinely entrusted itself to Christ does not produce a will that declines. When the will balks, it reveals that the heart’s entrustment was incomplete—the person was approaching trust, not resting in it. A competing allegiance held the heart more deeply than Christ did. The will does not independently adjudicate what the heart has decided. It enacts what the heart has embraced.
The apostolic mission aims “to bring about the obedience of faith among all the nations” (Romans 1:5; cf. 16:26). This phrase is widely understood in contemporary scholarship to denote faith that issues in an obedient response.3,4
Notes
- Douglas J. Moo, The Epistle to the Romans, New International Commentary on the New Testament (Grand Rapids: Eerdmans, 1996), 50–55, 438–456, 655–658. These chapters explore lexical semantics and contextual meaning, illustrating how biblical terms such as “mind” (nous) and “heart” (kardia) convey distinct yet interrelated aspects of human personhood in response to God.
- Douglas J. Moo, The Epistle to the Romans, NICNT (Grand Rapids: Eerdmans, 1996), 50–55, 438–456, 655–658. These sections address Romans 1:5 (“obedience of faith”), Romans 7 (inner conflict of knowing, desiring, and acting), and Romans 10:10 (belief with the heart and confession with the mouth), showing faith as a holistic response engaging mind, heart, and will.
- Thomas R. Schreiner, Romans, Baker Exegetical Commentary on the New Testament (Grand Rapids: Baker Academic, 1998), 35, 815. These pages exegete Romans 1:5 and 16:26, presenting “obedience of faith” as active trust that naturally issues in obedient response rather than passive assent.
- Craig S. Keener, Acts: An Exegetical Commentary, vol. 2 (Grand Rapids: Baker Academic, 2013), 1105–1108. This section on Acts 3:19 treats metanoeō (repent) and epistrephō (turn) as the active turning of conversion, inseparable from receiving God’s appointed agent, contributing to the unified pattern.
- G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (New York: Charles Scribner’s Sons, 1922), s.v. “νοῦς,” “καρδία,” “θέλω,” “θέλημα,” “βούλομαι.” He defines καρδία as the seat of the rational, emotional, and volitional elements of human life—the moral and religious condition of the person—so the heart names the whole inner self. His νοῦς is the ruling faculty of mind, understanding, and reason, his θέλω carries willing, wishing, and desire, and his βούλομαι adds purpose and settled intent, implying the deliberate exercise of volition more strongly than θέλω does.