God deals with His people based on the covenant He makes with them. There are two covenants which God has made with His people : The Old Covenant and the New Covenant.
What is the difference between the Old Covenant and the New Covenant?
The Old Covenant is the covenant which God made with His people, the children of Israel. This covenant is the Law, written on two tablets of stone and in the book of the law. If the people of God continue to live according to the Law, they will be blessed. But, if they break the Law, they will be cursed. The apostle Paul wrote about the Law, “Cursed is everyone who does not continue in all things which are written in the book of the law, to do them.” (Gal 3:10) and, “the man who does them shall live by them.”
(Gal 3:12) The New Covenant is the covenant which God made with His Son, the Lord Jesus Christ, for the sake of His people. It is a covenant in which God deals with His people in a better way than in the Old Covenant. The writer of the book of Hebrews wrote, “by so much more Jesus has become a surety of a better covenant.” (Heb 7:22) This better covenant is the New Covenant.
What makes the New Covenant better than the Old Covenant?
First, the New Covenant was established on better promises than those of the Old Covenant (Heb 8:6). What are these better promises? God will put His laws in the mind of His people and write them on their hearts; not on the tablets of stone and in the book anymore. And, He will be their God, and they shall be His people. None of them shall teach his neighbor, and none his brother, saying, ‘Know the Lord,’ for all shall know Him, from the least of them to the greatest of them. For God will be merciful to their unrighteousness, and their sins and their lawless deeds He will remember no more. (Heb 8:10-12) How does God put His laws in the mind of His people and write them on their hearts? How does all of His people know the Lord without being taught to know Him? By the Holy Spirit who is given in Christ to abide in them (Gal 3:14).
Second, in the New Covenant the surety of the promises is not based on the obedience of the people of God, but on the obedience of the Son of God, Jesus. That is not how it worked in the Old Covenant. In the Old Covenant, the surety of the promises was based on the obedience of God’s people. If they obeyed, they would receive the promises. If they did not obey, they would not receive the promises. In the New covenant, the surety of the promises is no longer in the obedience of God’s people, but in the name of Jesus, because He has obeyed. They will not receive the promises because they do. They will only receive them because of what Jesus did.