234. Divine Law, Old Law, and New Law: Distinctions and Unity

Summary

This lecture explores Thomas Aquinas’s account of divine law as distinct from natural and human law, focusing on why divine law is necessary and how the Old Law and New Law relate to one another. Berquist examines the fourfold structure of law through Psalm 18, demonstrates the distinction between Old and New Law as perfect and imperfect species rather than entirely different kinds, and addresses the paradoxical Pauline notion of the ’law of sin’ (lex peccati) as a participation in law through punishment rather than proper legal obligation.

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Lecture Notes

Main Topics #

The Necessity of Divine Law #

Thomas identifies four reasons why divine law is necessary beyond natural and human law:

Supernatural End: Humans are ordered to eternal beatitude (divine knowledge and vision), which exceeds natural human capacity. Natural law alone cannot direct humans to this transcendent end.
Certitude of Truth: Human reason is uncertain in contingent matters; divine law provides certain guidance that reason cannot achieve through investigation alone.
Interior Acts: Natural and human law regulate only exterior behavior; divine law directs the interior acts and dispositions of the soul.
Comprehensiveness: Human law cannot prohibit all sins without impeding the common good; divine law prohibits all evils through its divine authority.

Psalm 18 as Illustration #

Berquist demonstrates how Psalm 18 encapsulates all four reasons:

“Law of the Lord is immaculate” (permitting no ugliness of sin) → 4th reason
“Testimony of the Lord is faithful” (on account of certitude of truth) → 2nd reason
“Converting the soul” (directs interior acts) → 3rd reason
“Bestowing wisdom upon little ones” (orders to supernatural end) → 1st reason

The Old Law and New Law: Perfect and Imperfect Distinction #

Thomas distinguishes the Old and New Laws not as entirely different species (like horse and ox) but as perfect and imperfect within the same species (like boy and man):

Old Law:

Ordered to earthly, sensible good
Restrains the hand (exterior acts)
Operates through fear of punishment
Prepares people for reception of Christ

New Law:

Ordered to heavenly, celestial good
Restrains the soul (interior acts)
Operates through love poured into hearts by grace of Christ
Fulfills the promise of eternal life

The Law of Sin (Lex Peccati) #

Thomas addresses St. Paul’s paradoxical use of “law” in Romans 7:23: “I see another law in my members, repugnant to the law of my mind.”

Key Distinction:

The law of sin is not law in the strict sense but law by participation (per participationem), specifically by way of punishment
It results from the loss of original justice and the vigor of reason
In irrational animals, sensuality operates as a direct law; in humans, it represents deviation from reason
Functioning as divine punishment, it deprives humans of their proper dignity

Key Arguments #

For the Necessity of Divine Law #

God’s intention for all humans is salvation and knowledge of truth (1 Timothy 2:4), which requires direction to supernatural ends
One eternal and perfect law must guide humans ordered to God Himself, not merely to natural ends
Human reason, though capable, is imperfect and uncertain; certainty requires divine revelation
Interior acts demand regulation beyond what exterior legal restraint can achieve

Against Divine Law Being Twofold (Objections Addressed) #

Objection: God is one king and one kingdom; therefore one law should suffice
Response: Just as a father gives different commands to boys and adults, God gives proportionate laws to those still imperfect (Old Law) and those more perfectly led (New Law)
Objection: There is one divine law because God intends one salvation for all
Response: The twofold divine law reflects the fact that creatures do not have themselves in similar ways regarding perfection and imperfection

On the Law of Sin (Addressing Objections) #

Objection: Law consists in reason; sin deviates from reason; therefore sin cannot be law
Response: The law of sin is law by participation through the order of divine justice as punishment; it follows from God’s justice that one deprived of original justice is led by sensuality
Objection: Hot-blooded inclination (fomes) obligates no one; thus it cannot be law
Response: Obligation pertains to law stricte dictum; the law of sin has the notion of law only insofar as it participates in divine law through the mode of punishment

Important Definitions #

Divine Law (lex divina): Law given by God directing humans to supernatural ends; includes both Old Law and New Law, providing certain guidance and comprehensive regulation of interior acts

Lex Peccati (law of sin): The inclination to sensuality resulting from loss of original justice; law by participation functioning as divine punishment rather than proper legal obligation

Fomes (hot-bloodedness/kindling): The metaphorical term for sensual inclination; compared to wood chips or kindling that fuel passion and deviation from reason

Old Law (lex vetus): The Mosaic law ordered to earthly good; restrains exterior acts through fear

New Law (lex nova): The law of Christ ordered to heavenly good; restrains interior acts through love

Translation of Law (translatio legis): The carrying over or transition from one law to another; St. Paul references this in Hebrews regarding the transition from Old to New Law and from Levitical to Christic priesthood

Examples & Illustrations #

The Boy and Man Distinction #

Thomas uses the distinction between a boy under a tutor (pedagogue) and an adult man to illustrate the relationship between Old and New Law—not difference in kind but in degree of perfection and maturity.

Exterior vs. Interior Acts #

Old Law Example: “If you steal your neighbor’s possession, you transgress”
New Law Example (Sermon on the Mount): “If you desire your neighbor’s possession in your heart, you have already committed a theft”
Further Example: “If you look at a woman with lust in your heart, you have already committed adultery” (Matthew 5)

Divine Justice and Punishment #

Berquist discusses how St. Paul had a “thorn in the flesh” (a stimulus or incitement) left in him to keep him from pride, illustrating how the law of sin functions as divine punishment.

Animal Law vs. Human Law #

Dog: Naturally barks (law of its nature); this inclination is proper law for the dog
Sheep: Naturally mild (law of its nature); aggression would be contrary to its law
Humans: Ordered by reason; sensuality represents deviation from reason, not proper law

Notable Quotes #

“The law of the Lord is immaculate, permitting no ugliness of sin” (Psalm 18, cited by Thomas)

“Unless your justice abounds more than that of the scribes and Pharisees, you will not enter into the kingdom of the heavens” (Matthew 5:20, cited by Thomas regarding interior acts)

“I see another law in my members, repugnant to the law of my mind” (Romans 7:23, St. Paul—the basis for Thomas’s treatment of lex peccati)

“He wishes all men to be saved and to come to a knowledge of the truth” (1 Timothy 2:4, cited as God’s unified intention for all humans)

“Distinction is a cause of number” (Principle cited by Thomas regarding why the Old and New Laws are two)

Questions Addressed #

Is Divine Law One or Many? #

Objection: One king, one kingdom requires one law; God intends the same salvation for all
Answer: The Old and New Laws are distinguished as imperfect and perfect in the same species (not as different kinds like horse and ox). Just as a father gives different commands proportionate to a boy’s and man’s capacity, God gives laws proportionate to humanity’s capacity at different stages

Why Is Divine Law Necessary? #

Answer: Natural and human law alone cannot direct humans to their supernatural end (eternal beatitude), provide certainty of truth, regulate interior acts, or comprehensively prohibit all evils

Is There a Law of Sin? #

Objection: Law consists in reason; sin deviates from reason; therefore the law of sin is not truly law
Answer: The law of sin is law by participation (per participationem) in the mode of punishment. It is the inclination to sensuality resulting from the loss of original justice, functioning as divine justice’s deprivation of man’s proper dignity

How Does the New Law Relate to the Old? #

Answer: The New Law is related to the Old as the perfect to the imperfect within the same species. The Old Law prepares through fear and exterior restraint; the New Law perfects through love and interior transformation. Christ’s teaching surpasses the scribal and Pharisaic understanding of the law by demanding interior rectitude, not merely exterior compliance.