Covenant are by nature meant to last forever, but in this case God has decided to cancel the covenant of favour with the people. God changed his mind because the people proved unworthy of the covenant.
There are instances in the bible in which God apparently changed his mind. Eli was in the chosen line of the high priests in Israel. It was the divine arrangement starting with Aaron, but when there was a contradiction of God’s holiness, as the sons of Eli became particularly hideous (1Samuel 3:10-14). And their father was not so concerned, but was probably contented that what will be will be and that God does not have a choice but to continue with his lineage in the choice of the high priest.
God showed him that he would not be put into a corner; that he has options, and he rejected him, and down the line, the line of high priesthood was changed (1Kings 2:27). When the Pharisees said that those who were shouting Hosanna at the sight of Jesus, should shut up, Jesus said if they do, the stones will immediately cry out (Luke 19:40).
Even the unfaithfulness of Adam, the first Man did not stop God in his tracks, God made another Adam, Jesus (1Corinthians 15:45), to fulfil his plan for men on earth. Jesus was faithful where Adam failed. God had the plan of bliss and pleasure for Adam and Eve as but it was as long as they followed in his ways.
When people reject the holiness of God he rejects them. That was what happened to King Saul, who had become content that now that he was in a privileged position of being the first king of Israel, he was immovable, even by God. But he got the shocker of his life when God said that he had replaced him already (1Samuel 13:9-14). He did not know that he was only as secure as he obeyed God.
There are two main covenants in the bible, the basis of which the bible is divided into two main parts. The foundation of the new treatment is the old. The Old Testament is now defunct, it is no longer sustained by God; it is now empty. When God gave his son, he gave his all, he went all in as it were for our salvation, for which the new covenant was made through the blood of Jesus. There are different ways to compare the new and old covenant as outlined in the book of Hebrews. There is the different in the priesthood, the blood of the covenant, the extent of the covenant.
Priesthood: The priesthood is the means the people are connected to God. While for the Old Testament there were imperfect priests, and appointed without an oath, Jesus is the High priest of the new covenant and everyone gets to be priests (1Peter 2:9). It was prophesied that their will be a priest forever after the order of Melchizedek, and that was Jesus. The point is that his priesthood will be unending.
The blood of the covenant: While the old covenant was based on the blood of goats and bulls which can only have relevant in the tabernacle on the earth, the blood of Jesus being the basis of the New Testament was taken to the very presence of God in heaven. It is superior one, which rendered the inferior no longer necessary. The New has come the old is done away with.
The extent of the covenant: The blood of Jesus does not just cover our sin as the blood of bulls and goats did. It changes us on the inside. The bible says that our conscience can be purged by the blood of Jesus and because of that God can come to dwell in us, because the blood gives us spiritual cleansing on the inside.
The church is called the body of Christ. So in a way, the covenant with us, is a covenant with Jesus himself.
The righteousness that we have been given is the righteousness of Jesus, not of works but by faith. Therefore, the new covenant confers righteousness on us. It makes us citizens of heaven. And for Christians, the bible says that God is faithful and just to forgive us our sins and to clean us from all unrighteousness, if we confess (1John 1:7-9).
Confession of sin is an expression of faith in the efficacy of the blood of Jesus. It is not just something to do to clear your conscience, it is goes deeper than that. It purges the conscience from dead works.
Sin led to man coming into disfavour, but through the gift of the righteousness of Jesus we have come into favour with God. This is not something we strive for, but something we have come into, not on your own account but on the account of Jesus.
Becoming part of the old covenant is by the reason of natural birth, and now in the case of the new covenant, it is spiritual birth (John 3:1- 9), because Jesus, our High Priest is now a life-giving Spirit (1Corinthians 14:45), connecting us to the endless life of God.
Even while he was on earth, Jesus at least on one occasion, distanced himself from those he was naturally related with. He said: “who is my mother, brother or sister? They are those who hear the word of God and obeyed it (Matthew 12:47-50).” There we see Jesus focused on his spiritual associations, and not his natural ones.
The book of John 1:12 says that as many as believed in him, he gave the power to be called sons of God, with all the privileges that comes with that. We are connected to God through Jesus.
Jesus was obedient to the death of the cross and was given a name that is above every other name, and when the name of Jesus is mentioned, all knees bow, and every tongue confess his lordship. His name is imbued with unquantifiable authority (Philippians 2:5-11). But the authority is for our use, since we are connected to him.
Jesus sent us forth to make disciples, to bring others into the same covenant we have come into through faith, because faith in Jesus connects us with the new covenant, the covenant of endless favour.