It is important to understand that Jesus came for the lost sheep of the house of Israel. The long awaited messiah of Israel came to preach the gospel to these lost sheep. However the vast majority of the sheep rejected their messiah and murdered him. There is a spiritual saying, Romans 1:16 , “first to the Jews, then to the Gentiles” Jesus came first to the lost sheep of the house of Israel, Matthew 15:24 this was Israel’s last opportunity in the current age to repent and believe the gospel. Matthew 23:38 Matthew 20:16 This parable teaches us that Israel, who GOD dealt with first would become the last and the Gentiles, who GOD dealt with last, would be first. Since the lost sheep of Israel rejected and murdered their messiah they would also become the enemy of the gospel and persecute the church. After the last vestiges of Israel entered the church after Pentecost it then became the time of the gentiles. Paul explains how the Israelites are blinded until all the gentiles have been called and chosen, put into the church by GOD. Romans 11:25
This calling of the gentiles was a mystery to carnal Israel , who considered gentiles unclean and called them dogs. Ephesians 3:3,4,5,6 Colossians 1:26,27 The carnal Israelites have a spiritual veil on them that prevents them from seeing the truth. 2 Corinthians 3:14,15,16 Isaiah prophesied of this, Isaiah 6:9,10 However, in the distant future GOD will lift the veil that covers Israel and all nations. Isaiah 25:7 Israel never obtained what they were seeking but the church , the elect 144000, the called and chosen saints did. Romans 11:7,8
The old covenant was given to Israel, so that by example and the blessings that GOD would pour out on them, other nations would see and desire to become part of Israel thus bringing all under the law so that all would be condemned and realize the need for a savior, the law was to draw all to Christ so that when the messiah was manifested all people would have known him, but it didn’t work out that way, instead Israel murdered their messiah.
The new covenant would primarily be preached to gentiles and that is why the Apostle Paul was chosen. Take note that of the 27 books of the New Testament 14 were written by Paul, indicating the focus of the gospel message was to gentiles, not Israelites. Even when James, Peter, John and Jude wrote , their letters were directed to the church only, that at that time was composed mostly of former gentiles, with the former Israelites rapidly becoming a minority due to dying off.
The day of Pentecost was the beginning of a new direction for the church that existed before Christ, going all the way back to Able, to Abraham, to Moses and finally to Christ. After Pentecost the mystery of the gentiles was made known that was foretold by the prophets. Haven’t you ever noticed the shift away from the Israelites to the gentiles? Paul desperately tried to preach to his fellow Israelites but most of the time they tried to kill him or blasphemed . Acts 18:6 Acts 13:45,46,47
Pentecost was loaf 2 of the church, the saints before Jesus were loaf 1 as symbolized by Leviticus 23:17. It is as though GOD gleaned Israel of the fruit HE could gather but the tree afterwards bore no fruit so HE cursed it. Matthew 21:19 , the fig tree here is carnal Israel, also in Luke 13:6,7,8,9 Hosea 9:10 Carnal Israel was stiff necked and hard hearted and remains so to this day.
We, as Christians, should not hate carnal Israel or any other people, we are to love them all and we understand that their fall was a blessing to us former gentiles. GOD will in the future graft Israel back into the olive tree, but they will be last because the gentiles accepted Christ while the vast majority of Israel did not. Acts 13:48 Romans 11:11,15
Pentecost was not the beginning of the church, it was a continuation of it to include the gentiles in the hope of salvation.
The carnal nation of Israel was GODS elect under the old covenant law. Exodus 19:5,6 Deuteronomy 7:6 The church is GODS elect under the new covenant . 1 Peter 2:9 Carnal Israel failed and broke their covenant. The church is now and has always been GODS spiritual Israel because the root of the olive tree in Romans 11 are the saints mentioned in Hebrews 11. The entire olive tree is the church therefore the church has existed before the old covenant was made.