'The time is coming when I will make a new covenant with the people of Israel and with the people of Judah . . . (Jeremiah 31:31)
God greatly desires to establish a close, personal relationship with his greatest creation - man (Genesis 1:26 - 27). One of the ways he will accomplish his goal is through new agreements with humans, both conditional and unconditional. The first mention of a better covenant in the Bible is in Genesis, where Noah is promised he and his household will be spared the great flood (Genesis 6:18). God also promised Noah, and indeed all mankind, that he would never again use water to destroy all life on the planet (9:12 - 15).
The BETTER agreement
The book of Hebrews tells us WHY what was offered through Jesus Christ is better than the old one made in the Old Testament.
6. But on the other hand, He has obtained a supremely more excellent ministry, as much greater as the superior covenant of which He is also Mediator, which was established upon superior promises. (Hebrews 8:6)
There are at least three SUPERIOR reasons why the new agreement made by God is far better and greater than anything he previously proposed to man.
Ancient Israel was not given the ability to obey their Creator both in the law's letter of the law and spirit (Romans 8:3). God promises with this agreement that, through the power and might of his Holy Spirit, he will personally write his laws and ways on man's mind.
'I will give My laws into their minds, and I will inscribe them upon their hearts; and I will be their God, and they will be My people' (Hebrews 8:10, see also Romans 8:1)
ALL our sins will be forgiven
The second reason why the covenant Jesus Christ offered in the Gospels is greater than anything that came before it is it promises ALL sins will be forgiven. In fact, the tremendous promise God makes is that our sins, once he forgives them, will NEVER, EVER be recalled or remembered by him!
12. For I will be merciful toward their unrighteousness, and their sins and their lawlessness I will not remember EVER AGAIN. (Hebrews 8:12)
It is only through the sacrifice and death of Jesus Christ the Savior that such an incredible and awesome forgiveness can be extended to man (Matthew 26:27 - 28).
Receiving an eternal inheritance
The third and final reason (promise) the proposed covenant is far greater than anything else is that those who love and obey God will receive an inheritance only HE can give.
15. And for this reason He is the Mediator of the New Covenant: in order that through His death . . . those who have been called might receive the promise of the eternal inheritance. (Hebrews 9:15)
Soon offered to all Israel
God's proposal to live forever is being offered to only a relative few now. It soon will be proposed to ALL Israel. It will ultimately be offer to all those who ever lived (Ezekiel 37, Jeremiah 31, Hebrews 8, etc.). Although only partially fulfilled during his first coming to earth, the primary mission of Jesus' SECOND coming will be to encourage man to accept God's will for them.
And the Lord, whom you seek, will suddenly come to His temple, even the MESSENGER OF THE COVENANT, in whom you delight. (Malachi 3:1)
Under the rule of Jesus, the world will come to know, respect, and keep God's law.
The awesome destiny
God made humans for a particular reason and purpose. Out of his perfect love, he wants to share ALL he has, forever, with as many beings as possible. First, however, he must develop in us holy righteous character, the same character he and Jesus have had eternally, so that we can fully appreciate all that he generously wants to give.
Ultimately, EVERY human will be given a FULL chance to hear and understand the gospel. They will then have to decide whether they wish to live the way of God or not. It is through his incredibly amazing new covenant that God fulfills his will to have countless billions of spiritual children just like him.