Overview

The covenant of grace delivers “by a Mediator” — and this section presents Him. It names the Mediator (Q36), how the Son became man (Q37–39), why the Mediator must be God and man in one person (Q38–40), His office (Q41–42), and His execution of the threefold office of Prophet (Q43), Priest (Q44), and King (Q45). This is the Larger Catechism’s Christology, the heart of its gospel, fuller than the Shorter’s.

The Questions & Answers

Q36. Who is the Mediator of the covenant of grace? A. The only Mediator of the covenant of grace is the Lord Jesus Christ, who, being the eternal Son of God, of one substance and equal with the Father, in the fulness of time became man, and so was and continues to be God and man, in two entire distinct natures, and one person, forever.

Scripture Proofs (ESV):

“For there is one God, and there is one mediator between God and men, the man Christ Jesus.” (1 Tim. 2:5, ESV)

“And the Word became flesh and dwelt among us.” (John 1:1, 14, ESV)

Further proofs: Gal. 4:4; Rom. 9:5; Col. 2:9; Heb. 7:24–25.

Q37. How did Christ, being the Son of God, become man? A. Christ the Son of God became man, by taking to himself a true body, and a reasonable soul, being conceived by the power of the Holy Ghost in the womb of the virgin Mary, of her substance, and born of her, yet without sin.

Scripture Proofs (ESV):

“…therefore the child to be born will be called holy—the Son of God.” (Luke 1:35, ESV)

Further proofs: Gal. 4:4; Heb. 2:14, 16–17; 4:15; Matt. 26:38.

Q38. Why was it requisite that the Mediator should be God? A. It was requisite that the Mediator should be God, that he might sustain and keep the human nature from sinking under the infinite wrath of God, and the power of death; give worth and efficacy to his sufferings, obedience, and intercession; and to satisfy God’s justice, procure his favour, purchase a peculiar people, give his Spirit to them, conquer all their enemies, and bring them to everlasting salvation.

Scripture Proofs (ESV):

“…the church of God, which he obtained with his own blood.” (Acts 20:28, ESV)

Further proofs: Heb. 9:14; 7:25–28; Rom. 3:24–26; 4:25; 1 Pet. 3:18.

Q39. Why was it requisite that the Mediator should be man? A. It was requisite that the Mediator should be man, that he might advance our nature, perform obedience to the law, suffer and make intercession for us in our nature, have a fellow-feeling of our infirmities; that we might receive the adoption of sons, and have comfort and access with boldness unto the throne of grace.

Scripture Proofs (ESV):

“For we do not have a high priest who is unable to sympathize with our weaknesses.” (Heb. 4:15–16, ESV)

Further proofs: Heb. 2:14, 16–17; Gal. 4:4–5; Rom. 5:19.

Q43. How doth Christ execute the office of a prophet? A. Christ executeth the office of a prophet, in his revealing to the church, in all ages, by his Spirit and word, in divers ways of administration, the whole will of God, in all things concerning their edification and salvation.

Q44. How doth Christ execute the office of a priest? A. Christ executeth the office of a priest, in his once offering himself a sacrifice without spot to God, to be a reconciliation for the sins of his people; and in making continual intercession for them.

Scripture Proofs (ESV):

“…he has appeared once for all at the end of the ages to put away sin by the sacrifice of himself.” (Heb. 9:14, 26, 28, ESV)

“…he always lives to make intercession for them.” (Heb. 7:25, ESV)

Q45. How doth Christ execute the office of a king? A. Christ executeth the office of a king, in calling out of the world a people to himself, and giving them officers, laws, and censures, by which he visibly governs them; in bestowing saving grace upon his elect, rewarding their obedience, and correcting them for their sins, preserving and supporting them under all their temptations and sufferings… and taking vengeance on the rest, who know not God, and obey not the gospel.

Scripture Proofs (ESV):

“The LORD says to my Lord: ‘Sit at my right hand, until I make your enemies your footstool.’” (Ps. 110:1–3, ESV)

Further proofs: 1 Cor. 15:25; Isa. 33:22; Matt. 18:17–18; 2 Thess. 1:8.

Exposition: Q36–37 confess the incarnation: the eternal Son, “of one substance and equal with the Father,” took “a true body, and a reasonable soul” of the virgin Mary’s substance, “yet without sin” — two distinct natures in one person forever. Q38–39 are the Larger Catechism’s distinctive jewel: why the Mediator must be both God and man. He must be God to bear the infinite wrath without sinking, to give His work infinite worth, and to conquer every enemy; He must be man to obey and suffer in our nature, to sympathize with our weakness, and to win for us adoption and bold access to God. Only the God-man can save. Q43–45 expound the threefold office: as Prophet He reveals God’s whole saving will; as Priest He offers Himself once and intercedes continually; as King He gathers, governs, defends, and rewards His people while subduing all enemies.

Connections

• WSC Q21–26 — the Redeemer; the two natures; the threefold office of prophet, priest, and king.
• WCF 8 (Of Christ the Mediator) — the full doctrine.
• Loci: Christology (person and natures); the threefold office (munus triplex); why the Mediator must be the God-man.

Pastoral & Practical Significance

The Larger Catechism’s Q38–39 are worth treasuring, for they show why our Mediator is exactly the Savior we need. Because He is God (Q38), His sufferings have infinite worth — so no sin is too great for His blood — and He is mighty to conquer every enemy that threatens you, including death itself. Because He is man (Q39), He has “a fellow-feeling of our infirmities” — He knows your weakness from the inside, having been tempted as you are — and through His humanity you receive adoption and “boldness unto the throne of grace.” In Christ the God-man, strength and sympathy meet: a Savior strong enough to save to the uttermost and tender enough to feel your every weakness. And His threefold office meets your every need: as Prophet He teaches you, as Priest He has atoned for you and prays for you, as King He rules, defends, and will not lose you. Whatever your need today, it is met in this Mediator.

For Memory & Reflection

• Memorize Q36, Q38, and Q39 — the why of the God-man Mediator; anchor verses: 1 Timothy 2:5 and Hebrews 4:15–16.
• Christ must be God (to save fully) and man (to sympathize fully). Which truth do I most need to lean on today?
• Which of Christ’s offices — Prophet, Priest, King — do I most neglect to rest in?