A Body of Divinity
A clear and warm exposition of the Westminster Shorter Catechism — God's attributes, the covenant of grace, justification, sanctification, and glorification.
God and His Attributes
The Chief End of Man
Thomas Watson opens his systematic theology with the first question of the Westminster Shorter Catechism: "What is the chief end of man?" The answer — "Man's chief end is to glorify God, and to enjoy him forever" — sets the frame for everything that follows. Watson insists that these two ends are not rivals but a unity. To glorify God is the highest enjoyment available to a rational creature, and the enjoyment of God is itself the most complete form of his glorification. Any theology that severs doxology from delight has missed both.
Watson anchors the duty of glorifying God in the whole testimony of Scripture:
1 Corinthians 10:31 — "Whether therefore ye eat, or drink, or whatsoever ye do, do all to the glory of God."He observes that God glorifies himself in all his works — in creation, in providence, in redemption — and that man, made in God's image, is the creature designed to reflect and render back that glory consciously and voluntarily. The fall has disordered this purpose; redemption restores it. Knowing what man is for is the only sound beginning for knowing what God is like.
The Nature of God
Watson defines God as "a Spirit, infinite, eternal, and unchangeable, in his being, wisdom, power, holiness, justice, goodness, and truth" — following the Catechism's answer to question four. He expounds each element carefully. God is Spirit: he has no body, no parts, no passions in the sense of uncontrolled emotional reactions driven by external forces. He is not composed of matter and form as creatures are. This is why all images of God are forbidden — not merely because they mislead, but because they are categorically impossible:
John 4:24 — "God is a Spirit: and they that worship him must worship him in spirit and in truth."
God is infinite — without boundary in any dimension. Watson applies this to space (God is omnipresent: Jeremiah 23:24), to knowledge (God is omniscient: Psalm 147:5), and to power (God is omnipotent: Job 42:2). God is eternal — without beginning or end, not merely living through endless time but existing outside it. Watson draws comfort from this: the God who entered into covenant with Abraham is the same God today, unaged and undiminished. God is unchangeable — what he is, he always has been and always will be. His purposes do not alter, his love does not cool, his word does not expire:
Malachi 3:6 — "For I am the LORD, I change not; therefore ye sons of Jacob are not consumed."
The Divine Attributes: Holiness and Why Knowing God Matters
Watson treats the holiness of God as the most fundamental of the moral attributes — the one that gives meaning to all the others. God's omnipotence is holy power; his omniscience is holy knowledge; his love is holy love. Holiness is not simply one attribute among equals but the quality that characterizes all the rest. The seraphim's perpetual cry reflects this primacy:
Isaiah 6:3 — "Holy, holy, holy, is the LORD of hosts: the whole earth is full of his glory."No attribute is repeated three times in Scripture; holiness alone receives this triple emphasis. Watson argues that the triple repetition signals not merely intensity but the Trinitarian holiness of the one God — Father, Son, and Spirit, each and together absolutely holy.
Against any purely speculative theology, Watson closes this section with a practical argument: knowing God is not an end in itself but a means to conformity with God.
2 Corinthians 3:18 — "But we all, with open face beholding as in a glass the glory of the Lord, are changed into the same image from glory to glory."The knowledge of God that does not transform the knower is not true theological knowledge but a dead orthodoxy. Watson's entire catechetical method is designed to make theology doxological and devotional, not merely academic — a characteristic of Puritan divinity at its best.
Sin, Grace, and Redemption
The Fall and Original Sin
Watson's treatment of sin is grounded in the federal theology of the Westminster Standards. Adam stood as the covenant head of the entire human race in the covenant of works. His single act of disobedience was not merely a private failure but a representative act, the legal consequences of which passed to every natural descendant:
Romans 5:12 — "Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned."Watson distinguishes the imputed guilt of Adam's first sin from the inherited corruption of nature that follows from it. Both are real aspects of original sin, and both must be addressed by the gospel. The guilt requires pardon; the corruption requires renewal.
Watson describes original corruption as a pervasive defilement of the entire person — understanding darkened, will perverted, affections disordered, conscience dulled. He refuses to locate sin in the body alone, as certain ascetic traditions do. The body is the instrument; the sinful nature is in the soul. This corruption is both total (affecting every faculty) and universal (present from conception: Psalm 51:5). It is not merely the tendency to commit certain sins but the fundamental orientation of the creature away from God and toward self. Watson emphasizes this to close every door of natural moral self-recovery: fallen man cannot repair himself any more than a dead man can restore his own life.
The Covenant of Grace and Christ as Mediator
Against the ruins of the covenant of works, God in his free mercy established the covenant of grace — a covenant in which God himself provides what he requires. The federal head of this covenant is the second Adam, Jesus Christ, whose obedience and suffering accomplished what Adam's failure forfeited. Watson traces this covenant through the whole Old Testament, seeing it promised in Genesis 3:15 (the proto-evangelium), ratified with Abraham (Genesis 17:7), and typified in the entire Mosaic sacrificial system before being fulfilled in Christ.
Christ as Mediator exercises three offices — prophet, priest, and king — and Watson insists that all three must be received together. The Christ who forgives (priest) also teaches (prophet) and rules (king). To accept Christ's priestly work while refusing his kingly authority is not saving faith but a presumptuous self-deception. Watson is equally insistent on the necessity of both Christ's active and passive obedience. His active obedience — his lifelong fulfillment of the law — is the positive righteousness imputed to the believer; his passive obedience — his suffering and death — is the satisfaction of the law's penalty. Both are needed:
Romans 5:19 — "For as by one man's disobedience many were made sinners, so by the obedience of one shall many be made righteous."
Justification by Faith and Imputed Righteousness
Watson's treatment of justification is one of the most precise in his Body of Divinity. Justification is a forensic act of God — a judicial declaration, not an infusion of righteousness. God declares the believing sinner righteous on the basis of a righteousness that is not the sinner's own but is reckoned (imputed) to his account. This is the heart of the Reformation's recovery of the gospel:
Romans 4:5 — "But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness."
Watson takes pains to distinguish justification from sanctification while insisting that they are inseparable in the ordo salutis. Justification changes the believer's standing before God; sanctification changes his condition within. The first is instantaneous and complete; the second is progressive and never complete in this life. Both are by grace, both are through union with Christ, but they must not be confused. Faith justifies not as a work or virtue in itself, but instrumentally — as the hand that receives the gift of Christ's righteousness. Watson quotes Paul's summary of his own aspiration:
Philippians 3:9 — "And be found in him, not having mine own righteousness, which is of the law, but that which is through the faith of Christ, the righteousness which is of God by faith."
The Christian Life
Adoption and Sanctification
Watson treats adoption as distinct from both justification and regeneration, though inseparable from both. In justification, the condemned criminal is pardoned; in adoption, the pardoned stranger is brought into the family of God and made an heir. This is an act of pure grace with no precedent in human law:
1 John 3:1 — "Behold, what manner of love the Father hath bestowed upon us, that we should be called the sons of God."Watson observes that John's exclamation ("what manner of love") signals that adoption surpasses ordinary categories of grace — it is not merely forgiveness but family membership, with all the privileges of access, provision, and inheritance that belong to sons.
Sanctification, which Watson treats immediately after adoption, is the Spirit's work of renewing the image of God in the believer. Unlike justification, it is not a once-for-all declaration but a lifelong process that is incomplete in this life:
2 Corinthians 7:1 — "Having therefore these promises, dearly beloved, let us cleanse ourselves from all filthiness of the flesh and spirit, perfecting holiness in the fear of God."Watson identifies two movements of sanctification — the mortification of sin (the negative side) and the vivification of grace (the positive side) — and argues that both must be in motion. A Christianity that is only about killing sin and not about cultivating grace, or only about cultivating grace while ignoring besetting sin, is defective on its own terms.
The Means of Grace
Watson is concrete and churchly about the means through which sanctification advances. He identifies three principal means: the Word, prayer, and the sacraments. The Word of God — read and especially preached — is the primary means of grace. It is the seed of the new birth (1 Peter 1:23), the food of the growing Christian (1 Peter 2:2), and the instrument the Spirit uses to convict, instruct, comfort, and conform the soul to Christ. Watson warns against a kind of spirituality that professes to love God while neglecting the Scriptures, as though one could maintain intimacy with a person by refusing to hear them speak.
Prayer Watson describes as the soul's breathing — evidence of spiritual life and the means of its continuation. The believer who neglects prayer will soon find his affections for God cooling, his resistance to temptation weakening, and his sense of the reality of the spiritual world fading. He grounds the duty and privilege of prayer in Christ's standing invitation:
Matthew 7:7 — "Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you."On the sacraments, Watson follows the Reformed tradition in treating baptism and the Lord's Supper as means of grace — signs and seals of the covenant promises — that confirm and nourish faith when received with understanding and faith. They do not convey grace mechanically, but they are not empty symbols either.
Perseverance of the Saints and Glorification
Watson defends the perseverance of the saints against those who hold that saving grace can be finally and totally lost. His argument is grounded primarily in the nature of the covenantal promise and the intercession of Christ. If the elect could perish, then Christ's prayer for his own in John 17 would be in vain — but it cannot be in vain, since the Father always hears the Son (John 11:42). Paul's chain of redemption in Romans 8:30 — "whom he justified, them he also glorified" — uses the past tense for glorification, treating it as already accomplished from God's perspective. Not one link in this chain is breakable.
Watson is careful, however, not to turn perseverance into presumption. The promise is not that believers will never fall into serious sin, but that they will not fall finally or totally. The Spirit will restore them through repentance and renewed faith. Watson ends his Body of Divinity with glorification — the final and full conformity to the image of Christ in soul and, at the resurrection, in body:
1 John 3:2 — "Beloved, now are we the sons of God, and it doth not yet appear what we shall be: but we know that, when he shall appear, we shall be like him; for we shall see him as he is."This beatific vision — seeing God face to face in Christ — is the final goal toward which all the preceding doctrines tend. The chief end of man is to glorify God and enjoy him forever; glorification is that end arrived at, fully and irreversibly.