Deuteronomy 18:21

KJV

And if thou say in thine heart, How shall we know the word which the LORD hath not spoken?

KJV (with Strong's)

And if thou say {H559} in thine heart {H3824}, How shall we know {H3045} the word {H1697} which the LORD {H3068} hath not spoken {H1696}?

Complete Jewish Bible

You may be wondering, 'How are we to know if a word has not been spoken by ADONAI?'

Berean Standard Bible

You may ask in your heart, “How can we recognize a message that the LORD has not spoken?”

American Standard Version

And if thou say in thy heart, How shall we know the word which Jehovah hath not spoken?

Commentary

### SUMMARY
Deuteronomy 18:21 voices a critical question from the heart of the Israelite community, immediately following God's severe warnings against false prophets and the promise of a true prophet like Moses. This verse articulates the people's legitimate concern: "How shall we, the ordinary people, discern the authentic word of the LORD from a deceptive or presumptuous utterance?" It highlights the deep-seated need for a reliable, verifiable method of distinguishing divine truth, setting the stage for God's immediate and practical answer in the subsequent verse.

### CONTEXT
* **Literary Context:** Deuteronomy 18:21 is situated within a broader section of Deuteronomy (chapters 12-26) that outlines the statutes and ordinances for Israel as they prepare to enter and settle the Promised Land. Specifically, chapter 18 focuses on the proper channels of divine revelation and the rejection of pagan practices. The preceding verses (e.g., [Deuteronomy 18:9-14](/deuteronomy/18-9 "Deuteronomy 18:9-14 - Warning Against Abominable Practices")) sternly warn against detestable practices like divination, sorcery, and necromancy, which were prevalent among the Canaanite nations. In stark contrast, [Deuteronomy 18:15-19](/deuteronomy/18-15 "Deuteronomy 18:15-19 - The Promise of a Prophet like Moses") promises the future raising of a true prophet "like Moses," through whom God would speak directly to His people. This promise is immediately followed by a grave warning in [Deuteronomy 18:20](/deuteronomy/18-20 "Deuteronomy 18:20 - Warning Against False Prophets") against any prophet who presumes to speak a word in the LORD's name without His command, or who speaks in the name of other gods. Verse 21 then naturally arises as the people's internal, practical question, anticipating the essential need for a test of authenticity, which God provides in [Deuteronomy 18:22](/deuteronomy/18-22 "Deuteronomy 18:22 - The Test of a True Prophet").

* **Historical & Cultural Context:** The ancient Near East was a hotbed of religious practices, many of which involved attempts to divine the future or manipulate spiritual forces through various forms of magic, omens, and communication with the dead. The Canaanites, whom Israel was to dispossess, were deeply entrenched in such practices, including child sacrifice, consulting mediums, and sorcery. Against this backdrop, God established Israel as a distinct nation with a unique covenant relationship, where direct communication from Him would come through His chosen prophets, not through pagan rituals. The question in Deuteronomy 18:21 underscores the practical challenge for a people surrounded by diverse spiritual claims to adhere solely to the LORD's revelation. It highlights the divine provision for Israel to remain pure and undefiled by the spiritual corruption of their neighbors, ensuring they would not be "like those nations" ([Deuteronomy 18:9](/deuteronomy/18-9 "Deuteronomy 18:9 - Do Not Be Like Those Nations")).

* **Key Themes:** This verse contributes significantly to several overarching themes in Deuteronomy and the broader biblical narrative. The primary theme is **Divine Discernment**, emphasizing the urgent necessity for God's people to accurately distinguish between authentic divine revelation and human or demonic deception. This concern for spiritual purity and obedience in the face of potential false prophets is paramount. Secondly, it highlights the **Authenticity and Authority of Prophecy**, underscoring the gravity of prophetic ministry and the absolute requirement for its divine origin; a word spoken in the LORD's name must genuinely originate from Him alone. Finally, the verse speaks to **God's Faithful Provision and Protection**, demonstrating His anticipation of His people's practical need for a verifiable test to safeguard them from false prophets and harmful spiritual influences. This divine concern for protecting His people from error and leading them in truth is a recurring motif throughout Scripture, echoed in the New Testament warnings against false teachers (e.g., [Matthew 7:15](/matthew/7-15 "Matthew 7:15 - Beware of False Prophets") and [1 John 4:1](/1_john/4-1 "1 John 4:1 - Test the Spirits")).

### EXPOSITION AND ANALYSIS
#### Key Word Analysis
* **Say (Hebrew, _'amar'_):** While often translated as "say" or "speak," in this context, when combined with "in thine heart," it refers to an internal deliberation, a thought process, or a question arising from one's innermost being. It's not necessarily an audible utterance but a profound, unvoiced query that weighs heavily on the mind. This emphasizes the genuine, practical concern of the people.
* **Heart (Hebrew, _lev_):** In biblical Hebrew, "heart" is not merely the seat of emotions but the center of one's intellect, will, and moral being. To "say in thine heart" means to ponder deeply, to consider thoughtfully, and to raise a fundamental question of discernment from one's core understanding and concern for truth. It signifies a sincere desire for clarity and guidance.
* **Know (Hebrew, _yada'_):** This verb implies more than just intellectual comprehension; it signifies an experiential, verifiable knowledge. The people are not asking for a theoretical understanding but a practical, tangible means by which they can discern, recognize, and confirm the divine origin of a prophetic utterance. It suggests a process of observation and verification, leading to a confident conviction.

#### Verse Breakdown
* **"And if thou say in thine heart,"**: This opening clause indicates an anticipated internal struggle or question that will arise within the community. It acknowledges the natural human need for certainty and clarity, particularly when faced with grave warnings about deception. The "heart" here signifies the inner thoughts, deliberations, and concerns of the people, highlighting that this is a genuine, practical dilemma they will face.
* **"How shall we know"**: This is the core rhetorical question of the verse, expressing the people's fundamental need for a method of discernment. It's a plea for a clear, unambiguous test to distinguish between true and false prophecy. The "we" emphasizes that this is a communal concern, affecting the entire nation's ability to follow God's will.
* **"the word which the LORD hath not spoken?"**: This final clause defines the object of their concern: identifying words that falsely claim divine origin. It underscores the danger of presumptuous or deceptive prophecy—words spoken in the LORD's name that He has not actually commanded, or words uttered under the influence of other deities. The question is how to protect themselves from such spiritual counterfeit.

#### Literary Devices
Deuteronomy 18:21 effectively employs a **Rhetorical Question** to highlight a critical theological and practical dilemma. The question, "How shall we know the word which the LORD hath not spoken?", is not posed for the people to answer themselves, but rather to set the stage for God's immediate and authoritative response in the subsequent verse (Deuteronomy 18:22). This device creates a sense of **Anticipation**, drawing the reader into the people's legitimate concern and building expectation for the divine solution. Furthermore, the verse implicitly uses **Contrast** by juxtaposing the authentic word of the LORD with words "which the LORD hath not spoken," thereby emphasizing the absolute distinction between divine truth and human or demonic falsehood. This literary technique underscores the gravity of spiritual discernment and the vital importance of adhering solely to God's revealed will.

### THEOLOGICAL AND THEMATIC CONNECTIONS
Deuteronomy 18:21 profoundly illustrates God's faithfulness and His desire for His people to walk in truth, free from deception. It reveals a God who anticipates the challenges His covenant people will face and provides them with clear, practical guidance. The question posed by the people reflects a deep theological understanding that God's word is singular, authoritative, and distinct from any human or pagan utterance. It underscores the principle that true prophecy must originate solely from the LORD, emphasizing His sovereignty over revelation. This verse also highlights the human responsibility to exercise discernment, not blindly accepting all claims but diligently testing them against divine standards. The integrity of God's communication is paramount, and His provision of a test ensures that His people can confidently distinguish His voice, fostering a relationship built on trust and truth.

* [Matthew 7:15](/matthew/7-15 "Matthew 7:15 - Beware of False Prophets")
* [1 John 4:1](/1_john/4-1 "1 John 4:1 - Test the Spirits")
* [Acts 17:11](/acts/17-11 "Acts 17:11 - The Bereans Tested the Scriptures")

### REFLECTION AND APPLICATION
The timeless principle embedded in Deuteronomy 18:21 remains profoundly relevant for believers today. In an era characterized by an abundance of information, diverse spiritual claims, and competing voices, the need for discerning God's word is more critical than ever. We are called to cultivate a spirit of discernment, not through suspicion, but through a deep commitment to truth and a reliance on the Holy Spirit. This involves diligently testing all teachings, prophecies, and spiritual claims against the unchanging standard of God's revealed Word, the Bible. Just as ancient Israel needed a verifiable method to identify true prophets, believers today must carefully examine what they hear and read, ensuring it aligns with the character of God, the teachings of Christ, and the consistent message of Scripture. This commitment to discernment protects us from deception, strengthens our faith, and guides us into a deeper walk of obedience and truth.

#### Questions for Reflection
* **In what areas of your life do you most struggle with discerning God's voice from other influences?**
* **How does a consistent engagement with Scripture equip you to "know the word which the LORD hath not spoken"?**
* **What practical steps can you take to cultivate a greater spirit of discernment in your daily life and in your consumption of spiritual content?**
* **How does the community of believers (the church) contribute to our collective ability to discern truth from error?**

### FAQ
**How does Deuteronomy 18:21 relate to the concept of modern-day prophecy?**

Answer: Deuteronomy 18:21, by posing the question of discernment, sets the stage for the enduring principle that any claim to divine revelation must be verifiable and consistent with God's established truth. While the direct office of the Old Testament prophet as a primary source of new, authoritative revelation has ceased with the completion of the biblical canon, the New Testament acknowledges a gift of prophecy (e.g., [1 Corinthians 14](/1_corinthians/14 "1 Corinthians 14 - Prophecy and Tongues")). For modern-day claims of prophecy, the same underlying principles of discernment apply. Any prophetic utterance must align perfectly with the already revealed Word of God (the Bible), build up the church, and ultimately come to pass if it involves a predictive element. If it contradicts Scripture or fails to materialize, it is not from God. The question in [Deuteronomy 18:21](/deuteronomy/18-21 "Deuteronomy 18:21 - How Shall We Know?") forces us to ask, "Is this truly God's word?" and [Deuteronomy 18:22](/deuteronomy/18-22 "Deuteronomy 18:22 - The Test of a True Prophet") provides the timeless test.

### CHRIST-CENTERED FULFILLMENT
Deuteronomy 18:21, with its urgent question of how to discern the true word of the LORD, finds its ultimate and perfect fulfillment in Jesus Christ. The promise of a "prophet like Moses" in [Deuteronomy 18:15](/deuteronomy/18-15 "Deuteronomy 18:15 - The Promise of a Prophet like Moses") is explicitly applied to Jesus in the New Testament (e.g., [Acts 3:22-23](/acts/3-22 "Acts 3:22-23 - Peter's Sermon on Jesus as the Prophet")). Jesus is not merely a prophet but the very Word of God incarnate ([John 1:1](/john/1-1 "John 1:1 - The Word Was God"), [John 1:14](/john/1-14 "John 1:14 - The Word Became Flesh")). His life, teachings, miracles, and ultimately His death and resurrection, perfectly validated His divine origin and the truth of His words. Unlike any human prophet, Jesus never spoke a word "which the LORD hath not spoken" because He was eternally one with the Father, speaking only what the Father commanded ([John 12:49-50](/john/12-49 "John 12:49-50 - Jesus Speaks the Father's Words")). Therefore, the question posed in [Deuteronomy 18:21](/deuteronomy/18-21 "Deuteronomy 18:21 - How Shall We Know?") is definitively answered in Christ: we know the true word of the LORD because it is embodied and perfectly expressed in Jesus, the one whom God has truly spoken through ([Hebrews 1:1-2](/hebrews/1-1 "Hebrews 1:1-2 - God Has Spoken by His Son")). He is the ultimate standard against which all other claims to truth must be measured.

Note: Commentary is generated by AI with a directive for Biblical fidelity. Always rely on the Holy Spirit for discernment. The Scripture text and cross-references are from verified, non-AI sources.