Why does Jesus alter Old Testament laws?
Why does Jesus say He came to fulfill the Law (Matthew 5:17) but then seemingly change many Old Testament laws?

Jesus’ Fulfillment of the Law

A Topical Bible / Encyclopedia Entry


1. The Context of Matthew 5:17

Matthew 5:17 states, “Do not think that I have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill them.” These words arise during what is often called the Sermon on the Mount (Matthew 5–7). In this discourse, Jesus is revealing the deeper intent and spiritual dimensions of the Law. His audience included His disciples, Jewish religious leaders, and crowds who had been taught traditional interpretations of Old Testament commands.

Any seeming contradiction between Jesus’ assertion that He “came to fulfill the Law” and the ways He modifies or clarifies commandments can be understood through examining the central purpose of the Law, the distinctions within its various provisions, and the significance of His messianic role.


2. The Concept of Fulfillment in Scripture

The Greek term translated “fulfill” (πληρόω, plēroō) carries the sense of “completing,” “bringing to full measure,” or “filling up.” In the Old Testament, messianic prophecies, ritual practices, and moral principles point forward to their ultimate culmination in the Messiah. Jesus’ life, death, and resurrection perfectly embody and complete the prophetic and redemptive trajectory established from Genesis onward.

Messianic Prophecies: From Isaiah’s “Suffering Servant” (Isaiah 53) to Micah’s prophecy of His birth in Bethlehem (Micah 5:2), the entire Old Testament testifies to what the Messiah would accomplish. Jesus’ fulfillment of these prophecies attests to His identity as the Christ.

Sacrificial System: The Law’s sacrificial rites and festivals prefigured a perfect atoning sacrifice. Hebrews 9:11–12 explains that Jesus “entered the greater and more perfect tabernacle … by His own blood,” indicating the once-for-all fulfillment of the ceremonial rituals.

Moral Foundations: The Law contains moral stipulations reflective of God’s unchanging righteousness (e.g., not stealing, lying, or committing adultery). Jesus does not discard these moral imperatives; rather, He clarifies and intensifies them (Matthew 5:21–30).


3. The Threefold Division of the Law

Biblical scholars often group Old Testament commandments into three overlapping categories: moral, ceremonial, and civil.

1. Moral Laws: These reflect God’s unchanging nature (e.g., the Ten Commandments in Exodus 20:1–17). Jesus fortifies these standards, calling individuals to purity of heart (Matthew 5:21–28).

2. Ceremonial Laws: These involve sacrifices, dietary laws, priestly regulations, and temple-based worship. In Christ, the final sacrifice has been made (Hebrews 10:10–14). As a result, New Testament believers are no longer bound to observe the Levitical sacrificial system, which has found its culmination in Him.

3. Civil Laws: These laws governed Israel’s theocratic society (e.g., property rights, penalties for theft). While these directives applied specifically to ancient Israel’s national life, we glean underlying moral principles for justice and societal order. Jesus’ kingdom transcends national boundaries, guiding all who follow Him toward righteous living.


4. Jesus’ Authority to Clarify or Expand

Though Jesus upheld the authority of the Law, He also demonstrated His authority as the Lawgiver (cf. John 1:1–3). When He says, “You have heard that it was said … but I tell you” (Matthew 5:21, 27, 31, 33, 38, 43), He is not dismantling the Law but bringing out its fullest moral implications.

Intensification of Moral Commands: For instance, He teaches that harboring anger is akin to murder in God’s eyes (Matthew 5:21–22). This deep heart-level approach magnifies the holiness required of God’s people.

Fulfillment of Ceremonial Types: Jesus pronounces Himself “Lord of the Sabbath” (Matthew 12:8), indicating that the Sabbath law’s ultimate goal is found in relationship with Him (cf. Hebrews 4:9–10).

Transformation of Covenant Practice: With New Covenant realities (Luke 22:20), the binding nature of certain Old Testament ceremonial practices changes due to Christ’s atoning work. Rather than contradicting the Law, this shift reveals its deeper purpose.


5. The New Covenant and Its Impact

Jeremiah 31:31 prophesied a New Covenant wherein God’s laws would be written on His people’s hearts. This covenant was inaugurated through Jesus’ sacrificial death and resurrection (Matthew 26:28). The Apostle Paul writes, “For Christ is the end of the law, to bring righteousness to everyone who believes” (Romans 10:4). The term “end” implies “goal,” meaning Jesus is the consummation or completion of the Law’s demands and predictions.

Under the New Covenant:

Believers approach God through Christ’s righteousness rather than the repeated sacrifices prescribed in the Old Testament system (Hebrews 7:27–28).

Ethical teachings endure as an outworking of the Holy Spirit’s transformation (Romans 8:4). The Spirit empowers believers to live out the moral excellence revealed in the Law.

Ceremonial systems are fulfilled; hence, they are no longer required as a means of covenantal identity or atonement (Colossians 2:16–17).


6. Harmony with the Old Testament

Jesus’ teaching does not conflict with the Old Testament but reveals its full flowering:

Greater Righteousness: Matthew 5:20 states, “Unless your righteousness exceeds that of the scribes and Pharisees, you will never enter the kingdom of heaven.” The heart-level transformation Jesus requires stems from the same holiness God always desired (Deuteronomy 6:5).

Unified Scriptural Message: From Genesis to Revelation, we see a coherent story of redemption. Archaeological discoveries, such as the Dead Sea Scrolls found in Qumran (dating from the third century BC to the first century AD), corroborate the extensive continuity in biblical manuscripts. The consistency of textual evidence further supports the integrity of the Law and Prophets that foretold the coming Messiah.

Historical Verification: Ancient historians like Josephus (Antiquities of the Jews) reference the roles of Jewish customs and leaders tied to the Law. Geographical confirmations (e.g., the remains of first-century synagogues in Galilee) align with Gospel accounts, illustrating the historical reliability of the context in which Jesus taught.


7. Historical and Archaeological Corroboration

1. Dead Sea Scrolls: These manuscripts affirm the accurate transmission of Old Testament books, showing that the Law Jesus referred to in His day aligns closely with Old Testament texts we have today.

2. Masada and Other Sites: Excavations in Israel (such as at Masada, near the Dead Sea) reveal the extent of Jewish laws and customs in daily life. Findings of ritual baths (mikva’ot) at these sites highlight the ceremonial purity laws upheld by first-century communities, providing concrete settings for Jesus’ teachings.

3. Geological and Global Flood Accounts: While the primary focus here involves the Law, the geological evidence that many interpret as supporting a global flood (Genesis 6–9) further upholds the reliability of Scripture’s historical narrative, linking God’s covenant promises before and after this event to the ultimate covenant in Christ.


8. Conclusion

Jesus’ statement in Matthew 5:17 that He came “not to abolish but to fulfill” the Law is a comprehensive declaration that He is the culmination of the Old Testament’s moral, prophetic, and ceremonial elements. Although some commandments underwent transformation by virtue of the New Covenant, they were not discarded as irrelevant. Instead, they were brought to their intended goal in Christ. Through Him, the moral law is internalized by the Holy Spirit, the sacrificial rituals find their perfect sacrifice, and the civil laws of ancient Israel teach underlying principles still applicable in guiding ethical and just living today.

By harmonizing these teachings with historical and archaeological evidence, one sees that Jesus’ fulfillment of the Law emerges from a consistent scriptural narrative. From the Dead Sea Scrolls to contemporary confirmations of biblical accuracy, the reliability of the Old Testament foundation stands firm. Jesus, as the incarnate Word, fulfills every jot and tittle of God’s revelation, offering salvation and covenantal relationship to all who believe. As such, the seeming changes Jesus enacts are the proper and intended outworking of the Law’s ultimate purpose—to point to Him and to transform hearts for God’s glory.

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