1. The Covenant of Grace is Rooted in Eternity

Before time began, God ordained a Covenant of Grace in Christ for the salvation of His elect. This covenant was not an afterthought but an eternal decree.
- 2 Timothy 1:9 – “Who saved us and called us to a holy calling, not because of our works but because of his own purpose and grace, which he gave us in Christ Jesus before the ages began.”

2. Christ is the Mediator of the Covenant of Grace

Unlike the Covenant of Works, which depended on Adam’s obedience, the Covenant of Grace is secured entirely by Christ’s obedience and atonement.
- Hebrews 8:6 – “But as it is, Christ has obtained a ministry that is as much more excellent than the old as the covenant he mediates is better, since it is enacted on better promises.”

3. The Covenant of Works and the Covenant of Grace are Distinct

Petto carefully distinguishes the Covenant of Works (which required perfect obedience for life) from the Covenant of Grace (which provides salvation through faith in Christ’s righteousness).
-  Romans 3:20-22 – “For by works of the law no human being will be justified in his sight... But now the righteousness of God has been manifested apart from the law… the righteousness of God through faith in Jesus Christ for all who believe.”

4. The Old and New Covenants Are Administrations of the Same Covenant of Grace

The Old Testament saints were saved in the same covenantal framework as New Testament believers, though under different administrations.
- Hebrews 11:13 – “These all died in faith, not having received the things promised, but having seen them and greeted them from afar.”

5. Justification is Based on Christ’s Imputed Righteousness

In the Covenant of Grace, sinners are justified not by works, but by faith in Christ, whose righteousness is credited to them.
- Romans 4:5 – “And to the one who does not work but believes in him who justifies the ungodly, his faith is counted as righteousness.”

6. The Covenant of Grace is Unbreakable for the Elect

Once a believer is in the Covenant of Grace, God will never forsake them, for it is secured in Christ’s finished work.
- Jeremiah 32:40 – “I will make with them an everlasting covenant, that I will not turn away from doing good to them.”

7. The Covenant of Grace Includes Both Promises and Duties

Although salvation is entirely by grace, the covenant includes obligations such as faith, repentance, and obedience, which are fruits of grace rather than conditions for salvation.
- John 15:10 – “If you keep my commandments, you will abide in my love, just as I have kept my Father’s commandments and abide in his love.”

8. The Sacraments are Signs and Seals of the Covenant

Baptism and the Lord’s Supper are covenantal signs that point to God’s promises and confirm the faith of believers.
- Romans 4:11 – “He received the sign of circumcision as a seal of the righteousness that he had by faith while he was still uncircumcised.”

9. The Covenant of Grace is the Key to Understanding Redemptive History

The entire Bible is structured around God’s covenantal dealings with His people, from Adam to Christ.
- Galatians 3:16 – “Now the promises were made to Abraham and to his offspring. It does not say, ‘And to offsprings,’ referring to many, but referring to one, ‘And to your offspring,’ who is Christ.”

10. Assurance of Salvation Flows from Covenant Promises

Believers can have full assurance of salvation because God’s promises in the Covenant of Grace cannot fail!
- Hebrews 6:17-18 – “So when God desired to show more convincingly to the heirs of the promise the unchangeable character of his purpose, he guaranteed it with an oath.”

These key lessons from The Great Mystery of the Covenant of Grace by Samuel Petto offer a rich theological foundation for understanding God’s redemptive plan in Christ. This book is a must-read for anyone who wants to deepen their understanding of covenant theology!