1. So we are not in Matt, Mark, Luke and John huh.
Not dispensationally, no. In the gospels Jesus spoke primarily to the Jews, but many Gentiles received from Jesus ministry. Even as there have been Gentiles in the past who were blessed in one way or another through the Jews, according to God's mercy and ultimate plan of redemption.
However his work on the cross is for everyone- Jew and Gentile.
So we should disregard grapes and bread?
Not dispensationally, no. On the night of Jesus being betrayed and his arrest, at their last meal together, the disciples partook of the new covenant using the wine as the blood of Jesus, and bread as his body. They did it ahead of time., to remember his crucifixion and the covenant benefits from it to those who believe in him through his work on the cross.
That work spans backward in time to all those of the Old Testament who looked forward to salvation, depicted by animal sacrifices. They only had the promise of it (Some are mentioned in Hebrews chapter 11) And it spans forward in time to include all of us, who get in on the fulfillment.
2. The Samaritan woman was saved and she was non Jew.
The Samaritan woman was not saved/born again. The Jews had and still have a measure of the fountain and well of life. It is depicted by the natural well, Jesus's speaking of it in that way was not new. But perhaps new to the Samaritan woman. However, Jesus spoke of a greater measure that can only be found in him.
No one could be saved/born again until after Jesus' crucifixion and resurrection. The remaining disciples and those that make up the 120 in the upper room on the fulfillment of Pentecost (a Jewish moed as Passover is) were not saved/born again until that moment.
3. Peter went into Cornelius house and was saved. He was a gentile.
Cornelius and his household were saved/born again. As Jesus spoke of in John 17, "Neither pray I for these (his disciples) alone, but for them also who shall believe on Me through their word (message, testimony)."
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This is a brief explanation of the dispensational topic.
In Matthew 24:3 the disciples asked Jesus, "What will be the sign of your coming and of the end of the age?" An 'age' is referring to a dispensational point of time in a timeline span of years.
The Jews have a dispensational chart that spans 7000 years, or 7 prophetical days. This is where I believe Peter's statement fits in when he wrote. "A day is as a thousand years, and a thousand years is as a day."
The apostle Paul wrote in Galatians 4:4, "When the fulness of the time came, God sent for His Son.." In Luke 2:25-26 it states that there was a man named Simeon who was looking for the consolation of Israel. And the Lord revealed to him by the Holy Spirit, that he would see the Lord's Christ- the Messiah.
Jesus was born on the earth close to the end of the fourth dispensation. According to what Daniel had been told. From his perspective that Jesus would arrive. Based on that timeline, the maji (descendants of the group formed by Daniel, the chief magi) traveled to welcome the Christ at his birth.
The church age has been living in the prophetic days 5-6. We are now living in the closing of the 6th day. Seeing signs of an approaching time of the seven year tribulation. The prophetical week that Daniel and the apostle John wrote of. Which will culminate in the 7th day, the Millennium.