Israel and Judah did not remain faithful, the marriage agreement-- the old covenant -- was broken. "And I saw, when for all the causes whereby backsliding Israel committed adultery I HAD PUT HER AWAY, AND GIVEN HER A BILL OF DIVORCE; yet her treacherous sister Judah feared not, but went and played the harlot also" (Jer. 3:8).
The relationship became so bad that God was finally forced into divorcing His own people. He first sent Israel into captivity by the Assyrians and later Judah by the Babylonians (Ezek. 23).
Let's observe the fault with the first covenant now that we've seen what happened to it.
What was the Fault?
With the Old Covenant?
Paul said in the book of Hebrews that the fault with the old covenant was not in the laws, but in the people. But why and how? Because it was not possible for them to remain faithful to the righteous conditions God had prescribed in His covenant. "O that there were such an heart in them, that they would fear me, and keep all my commandments always that it might be well with them" (Deut. 5:29). Here was the weakness of the old covenant. THE PEOPLE DID NOT HAVE THE SPIRITUAL STRENGTH OF CHARACTER TO BE FAITHFUL TO THEIR VOW TO KEEP A SPIRITUAL LAW. The law was "weak through the flesh" (Rom. 8:3). The righteousness under the first covenant was to be accomplished only through human obedience, fleshly effort, because there was NO SPIRITUAL PROMISE OF RECEIVING THE HOLY SPIRIT TO GIVE SPIRITUAL POWER TO KEEP A SPIRITUAL LAW. Israel could not serve God because they did not have a God-fearing nature within them that the new covenant offers.
How the Fault Will Be Corrected
Remember that the first covenant had the spiritual laws written on two tables of stone and the civil laws written in a book. Obedience had to come from carnal flesh alone, with NO spiritual help from God. But look what the new covenant has to offer fleshly human beings.
It won't be according to the agreement made with ancient Israel. Notice the differences: "For this is the covenant that I will make with the house of Israel after those days, saith the Lord; I will put my LAWS into their mind, and write them in their hearts" (Heb. 8:10; Jer. 31:33).
So there will be laws, God's laws, the SAME laws which stand fast for ever and ever (Ps. 111:7-8); but this time they will be written in the hearts and minds of the people. They will be "written not with ink BUT WITH THE SPIRIT OF THE LIVING GOD; not in the tables of stone, but in the fleshly tables of the heart" (11 Cor. 3:3).
The new covenant will be made only with those who God's law is indelibly written in their thoughts and actions. And what is the power that writes God's laws in our hearts and minds? "The Spirit of the living God."
The love of God which fulfills the law is "shed abroad by the Holy Spirit which is given unto us" (Rom. 5:5). The Holy Spirit is one of the BETTER promises of the new covenant (Heb. 8:6).
The new covenant will be made with Israel--the house of Israel and the house of Judah. The new covenant will NOT be made with those who REMAIN Gentiles as most people assume. The covenants and promises pertain to Israel (Rom. 9:4).
Since the new covenant will be made with Israel, what about the Gentiles? Are they totally left out? Or has God provided some way by which they may receive the same blessings which are promised to Turned?
How Gentiles Can Enter
Ephesians, the second chapter, Paul wrote to those who were "in time past Gentiles in the flesh that at that time were WITHOUT Christ." Why? "Being aliens from the commonwealth of Israel, and strangers from the covenants of promise, having no hope, and without God in the world." How can Gentiles come into the same promises that were granted Israel? The next verse tells us. "But now IN CHRIST JESUS ye who sometimes were far off are made nigh by the blood of Christ" (Eph. 2: 13).
Only THROUGH Jesus Christ can Gentiles be "no more strangers and foreigners, but fellow citizens with the saints" (Eph. 2:19). Paul states in Gal. 3:29, "And IF YE BE CHRIST'S, then are ye Abraham's seed (no longer considered Gentiles) and heirs according to the promise."
Gentiles must belong to Christ in order to become part of the spiritual commonwealth of Israel -- the church. In Rom. 11:17-18, Paul pictures the Gentiles as branches of wild olive trees who are grafted into the natural olive tree -- Israel begotten of the Holy Spirit. Once being IN Christ, Gentiles can be partakers of the same Spirit of promise and of the blessings to Israel. The Gentiles by nature do not receive the promise. They must become transformed into the Spirit-begotten commonwealth of Israel before they can receive any of the blessings.