Reformed Dogmatika

One Covenant of Grace: Promise, Shadows, and Fulfillment

Ancient olive tree beside stone walls at sunset

Covenant theology study chart

One Covenant of Grace: Promise, Shadows, and Fulfillment

An old and new covenant chart with Scripture and support from six Reformed standards

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The covenant of grace is God’s promise to save sinners through Jesus Christ, received by faith. Abraham’s household, Israel under Moses, and the church after Christ’s coming stand within a history of promise and fulfillment. The outward administration changes; the Savior and the saving grace he gives remain the same.

With gratitude to Derek Radney, whose chart, Continuity and Discontinuity between the Old (Mosaic) and New (Eternal) Covenants, prompted this study. Radney supplied the original comparative framework. The wording, expanded comparisons, confessional references, and qualifications below are Reformed Dogmatika’s own work; they should not be attributed to him.1


One Covenant of Grace

There are not therefore two covenants of grace, differing in substance, but one and the same, under various dispensations.2

Westminster Confession of Faith 7.6

“Dispensations” here means different historical administrations. The confession affirms one covenant of grace and one salvation in Christ. This comparison follows that confession’s account of the Mosaic administration. Reformed theologians differ over how the Sinai covenant also displays the demand for obedience given to Adam. This chart follows the Westminster Confession’s account without attempting to settle that debate.


Promise, Shadows, and Fulfillment

Read across each comparison to trace the promise through Abraham, the Mosaic administration, and fulfillment in Christ. Follow the Scripture references, then consult the corresponding confessional support below.

ComparisonAbrahamic promiseMosaic administrationNew covenant in Christ
01. One saving promise↑ Comparison topics

God promised to be Abraham’s God and to bless the nations through his offspring. The gospel was announced beforehand.

Genesis 17:7; Galatians 3:8,16

Israel received the promises through an administration with priests, sacrifices, and other shadows of Christ.

Exodus 19:4-6; Hebrews 10:1

Christ fulfills the promise. Believing Jews and Gentiles receive Abraham’s blessing and the promised Spirit through him.

Galatians 3:13-14,29

02. The outward covenant community↑ Comparison topics

Abraham’s household received the covenant sign, including infant sons and servants. Receiving the sign did not establish that every recipient had saving faith.

Genesis 17:10-14,23-27; Romans 4:11

Israel included believers and unbelievers within its national covenant life. Common privileges did not prevent judgment.

Deuteronomy 29:10-13; 1 Corinthians 10:1-5

The visible church includes those who profess the true faith and their children. Outward membership is real, while saving union with Christ belongs to those renewed by the Spirit.

Acts 2:38-39; 1 Corinthians 7:14; Romans 9:6

03. Believers’ children↑ Comparison topics

God included Abraham’s children in the covenant administration before they could profess faith for themselves.

Genesis 17:7,10-12

Children stood with their parents before God and were taught to love and obey him.

Deuteronomy 6:6-7; 29:10-13

The Reformed case for infant baptism joins covenant continuity with the promise to believers’ children and their consecrated place within the church. A child’s baptism calls for lifelong faith.

Acts 2:39; 1 Corinthians 7:14; Colossians 2:11-12

04. Christ the saving head↑ Comparison topics

Abraham received God’s promises and believed them. Christ, Abraham’s promised offspring, is the saving head; Abraham himself is not a substitute redeemer.

Genesis 15:6; Galatians 3:16

Moses served as mediator of the Sinai administration. He was a servant who pointed forward to Christ.

Deuteronomy 5:5; Hebrews 3:1-6

Jesus is the mediator of the new covenant and the second Adam. His saving work benefits his elect in every age.

Romans 5:15-19; Hebrews 9:15

05. Forgiveness and sacrifice↑ Comparison topics

Abraham was justified by faith. David’s testimony likewise describes real forgiveness received apart from works.

Romans 4:1-8

Repeated sacrifices pointed to Christ. Animal blood could not remove sin, yet Old Testament believers received full forgiveness through the promised Messiah.

Hebrews 9:15; 10:1-4; Psalm 32:1-2

Christ has offered the decisive sacrifice once for all. No further offering for sin is needed; his people receive the forgiveness promised in Jeremiah.

Hebrews 10:10-18; Jeremiah 31:34

06. Knowing God and access to him↑ Comparison topics

Abraham knew God by faith, and the promise directed his household to walk before the Lord.

Genesis 17:1; Hebrews 11:8-10

Believers truly knew God, but the sanctuary’s barriers and priestly system displayed restricted ceremonial access.

Psalm 23:1-6; Hebrews 9:6-8

All who share Christ’s saving benefits know the Lord. Every believer approaches the Father through the Son by the Spirit, without a privileged priestly caste.

Jeremiah 31:34; Ephesians 2:18; Hebrews 10:19-22

07. The Spirit and a renewed heart↑ Comparison topics

Saving faith was God’s gift. The promise was received by believers looking forward to Christ.

Romans 4:16-22; Hebrews 11:13

God commanded heart obedience and promised heart circumcision. Old Testament saints already experienced the Spirit’s renewing work.

Deuteronomy 10:16; 30:6; Psalm 51:10-12

The exalted Christ pours out the Spirit. The new covenant brings greater fullness and clarity, while regeneration remains necessary for every sinner.

Acts 2:16-18,33; John 3:3-8

08. Law written on the heart↑ Comparison topics

Abraham’s faith bore fruit in obedience. God’s commands were received within the promise.

Genesis 17:1; 26:5

The moral law declared God’s will; ceremonial and national laws governed Israel. The law exposed sin and could not justify sinners.

Deuteronomy 6:5-6; Romans 3:20

God writes his law on hearts and produces grateful obedience. Christ fulfills the ceremonial shadows; the moral law remains a rule of life for believers.

Jeremiah 31:33; Romans 8:3-4; Ephesians 2:14-16

09. Faith and obedience↑ Comparison topics

Abraham trusted God’s promise. His obedience expressed that faith rather than earning justification.

Genesis 15:6; Romans 4:9-12

Israel was called to faith and obedience. The Spirit enabled believers to obey, even though the law itself could not create spiritual life.

Deuteronomy 30:6; Hebrews 4:2

Christ’s righteousness is received by faith alone. The Spirit produces obedience as the fruit of salvation; our works do not become its ground.

Ephesians 2:8-10; Romans 6:1-4

10. Covenant permanence and breach↑ Comparison topics

God’s promise would reach its appointed fulfillment. Nevertheless, outward participation and saving faith must be distinguished.

Genesis 17:7,14; Romans 9:6-8

Israel violated the Sinai covenant and suffered exile. Jeremiah identifies this covenant as the one God made when he brought Israel out of Egypt.

Jeremiah 31:32; Deuteronomy 28:58-68

Christ secures salvation for his people. Professing members can despise covenant privileges and apostatize; those truly united to Christ are preserved and cannot finally lose salvation.

Hebrews 10:26-31; John 10:27-29; 1 John 2:19

11. Discipline and final judgment↑ Comparison topics

Exclusion from the covenant community was a serious warning. The sign required covenant loyalty; mere ancestry did not guarantee salvation.

Genesis 17:14; Romans 9:7-8

Israel’s national sanctions included famine, defeat, and exile. These belonged to the Mosaic administration of life in the land.

Leviticus 26:14-39; Deuteronomy 28:15-68

The church disciplines unrepentant members. God also corrects his children as a Father; final condemnation belongs to unbelief. Illness alone does not prove a particular covenant offense.

1 Corinthians 5:1-5; 11:27-32; Hebrews 12:5-11; John 9:1-3

12. Signs of admission and fellowship↑ Comparison topics

Circumcision marked covenant membership and sealed the righteousness of faith. Abraham’s household also shared sacrificial worship.

Genesis 17:10-14; Romans 4:11

Circumcision continued; Passover and sacrifices ordered Israel’s worship. The Sabbath was also a sign of the Sinai covenant.

Exodus 12:43-49; 31:13-17

Baptism marks admission into the visible church and signifies Christ’s saving benefits. The Lord’s Supper nourishes believers. Neither sacrament works automatically.

Matthew 28:19-20; Romans 6:3-4; 1 Corinthians 10:16; 11:28

13. Worship after fulfillment↑ Comparison topics

Promise and sacrifice directed faith toward the redemption God would provide.

Genesis 22:8,13-18

The blood of sacrificial animals and the sanctuary’s arrangements foreshadowed Christ’s work.

Hebrews 9:1-10; 10:1

Christ’s shed blood ends the need for sacrificial bloodshed. Word, baptism, and the Supper proclaim his finished work. The Lord’s Day remains for worship and rest.

Hebrews 10:18; 1 Corinthians 11:26; Acts 20:7

14. Land and inheritance↑ Comparison topics

God promised Abraham land and blessing for the nations. Abraham looked beyond Canaan to a heavenly homeland.

Genesis 12:1-3,7; Hebrews 11:8-16

Israel’s life in Canaan depended on covenant faithfulness. The land and its rest pointed beyond themselves.

Deuteronomy 28:1-14; Hebrews 4:8-11

The inheritance reaches its fulfillment in Christ and the renewed creation. Believing Gentiles share the promise with believing Jews.

Romans 4:13; Galatians 3:29; Revelation 21:1-4

15. Already fulfilled, awaiting glory↑ Comparison topics

Believers trusted promises whose historical fulfillment they had not yet seen.

Hebrews 11:13,39-40

The prophets announced a new covenant, a cleansed people, and God’s enduring presence among them.

Jeremiah 31:31-34; Ezekiel 36:25-27; 37:26-28

Christ has inaugurated the new covenant through his death. His church still needs teaching and discipline; at his return his people will enjoy perfected fellowship with God.

Luke 22:20; Hebrews 8:6-13; Ephesians 4:11-16; Revelation 21:3-4


Reading Jeremiah 31 with Hebrews

Jeremiah contrasts the promised new covenant with the covenant made when God brought Israel out of Egypt. Hebrews identifies Jesus as its mediator and connects Jeremiah’s promises to his completed sacrifice (Jeremiah 31:31-34; Hebrews 8:6-13; 10:14-18). We shouldn’t postpone the whole promise until the final state: Christ has already inaugurated it.

Knowing God belongs to the saving blessings of this covenant. The phrase “from the least of them to the greatest” spans the people without a privileged spiritual class. It does not, by itself, identify the recipients of baptism or prove that every outward church member is regenerate. The Reformed argument for baptizing believers’ children draws on the wider covenant pattern and the church’s confessional teaching.

Jeremiah’s promise does not abolish Christian teaching, which the apostles continue to command (Matthew 28:20; Ephesians 4:11-16). Nor does it imply that Old Testament believers lacked saving knowledge of God. The advance is bound to Christ’s accomplished redemption and the fuller administration of its benefits.


Outward Membership and Saving Grace

Baptism is a sign and seal of the covenant of grace and marks admission into the visible covenant community of believers and their children. The church recognizes membership according to God’s revealed rule; it cannot inspect the secret decree of election. Outward membership does not guarantee regeneration (WCF 25.2; 28.1,4-6; WLC 61-62; HC 74).

New Testament warnings address people who share the church’s privileges and may yet turn from Christ. Those warnings must be taken seriously. They don’t overturn Christ’s promise to preserve everyone truly united to him (Hebrews 10:26-31; John 10:27-29; WCF 17.1). It is clearer to speak of despising the covenant’s outward administration than to suggest that Christ’s saving covenant fails.


Confessional Support

WCF = Westminster Confession of Faith; WLC = Westminster Larger Catechism; WSC = Westminster Shorter Catechism; BC = Belgic Confession; HC = Heidelberg Catechism; CD = Canons of Dort. These are study references, not quotations. Not every standard directly addresses every comparison.

ComparisonConfessional references
01. One saving promiseWCF 7.3,5-6; WLC 30-35; WSC 20; HC 19
02. The outward covenant communityWCF 25.1-2; 28.1,5; WLC 61-66; BC 29,34; HC 74
03. Believers’ childrenWCF 28.4; WLC 166-167; WSC 95; HC 74; BC 34; CD I.17
04. Christ the saving headWCF 8.1,6; WLC 31,36; WSC 21; BC 21-22
05. Forgiveness and sacrificeWCF 7.5; 8.5-6; 11.6; WLC 34; WSC 25,33; HC 66-67; BC 21,23
06. Knowing God and access to himWCF 20.1; WLC 35,55,65; HC 31-32; BC 26
07. The Spirit and a renewed heartWCF 7.5-6; 10.1; WLC 32-35,67; WSC 30-31; HC 65; CD III/IV.11-12
08. Law written on the heartWCF 19.3,5-6; WLC 97; WSC 39-42; HC 86,91; BC 25
09. Faith and obedienceWCF 11.1-2; 16.2; WLC 32,73; WSC 33,35; HC 60,86; BC 22-24; CD III/IV.14
10. Covenant permanence and breachWCF 17.1-3; 28.5; WLC 61,79; CD V.3,6-8; BC 29
11. Discipline and final judgmentWCF 17.3; 30.2-4; WLC 83; HC 82,85; BC 29,32; CD V.5-7
12. Signs of admission and fellowshipWCF 27.1-5; 28.1,5-6; 29.7-8; WLC 162-165,177; WSC 91-96; BC 33-35; HC 65-74,81
13. Worship after fulfillmentWCF 19.3; 21.7; 27.4; 29.2; HC 67-68,103; BC 25
14. Land and inheritanceWCF 7.6; 32.2; 33.2; WLC 65,90; WSC 38; BC 37
15. Already fulfilled, awaiting gloryWCF 7.6; 13.1-3; 33.2; WLC 75,90; WSC 35,38; BC 37; CD V.1-2

Read CD I.17 carefully: it comforts godly parents concerning children whom God calls from this life in infancy. It does not declare every baptized child elect. Likewise, CD III/IV.11-14 describes regeneration and faith, rather than providing a separate treatment of baptism.


Trusting the Promise in Church and Home

Parents can receive their children’s place in the covenant community with gratitude and teach them to trust Christ. The child who bears the sign still needs the Savior it signifies. The church’s task is to preach Christ, administer his sacraments faithfully, and call its members to repentance and faith. Jeremiah’s promise supplies confidence in God’s saving work while leaving no room for confidence in an outward badge alone.


Footnotes

  1. Derek Radney, Continuity and Discontinuity between the Old (Mosaic) and New (Eternal) Covenants, chart and accompanying X post, initially supplied as screenshots. Author’s updated chart, shared October 9, 2026, with typo corrections and a duplicate row removed. Author’s X profile. ↩︎
  2. Westminster Confession of Faith 7.6, concluding sentence. ↩︎

FURTHER STUDY

One Promise Two Covenant Signs compares circumcision and baptism with Scripture and confessional support.


The Covenant of Grace Explained: From Adam to Christ traces the one saving promise through redemptive history.


A Concise Case for Reformed Infant Baptism develops the case for baptizing believers’ children.

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