To my understand.
Many Jews and Pharisees were expecting to see their own King in power and glory, wear gold crown, fancy robe, with rod, ride on horse. They expect their important top ranked person to appear the world with glory and power to overthrown Roman Empire, and establish Judasism and religion political in Jerusalem to be the world's capitol.
When Jesus came to earth. He was not an important person, he was not a rich. He was very poor and humble. I am sure that he wore cheap robe or dress. Hard for Pharisees and Jews to believe that Jesus is the true Kinbg of Israel, because they were not able to reconginize Jesus is the son of God and truly King, because he was poor and dress in cheap clothing. Also, Jesus have no role or job on earth. He was just as servant.
Pharisees and Jews demanded their own King come in glory and power to overthrown Roman Empire, so, they expecting to see Kingdom appear earth in power. They have the wrong idea about Kingdom. Kinbgdom was not like as 'fanasty dream'.
Jesus told them, kingdom was not come with observation, it come within them. I believe he means that he is already present with them, they didn't realize that the King is already right there within few feet away from them. Jesus is the King. That why, they failed for recognize(notice) Jesus is the King. Actual, they rejected Christ as truly Messiah, King, and Son of God.
Premill believes kingdom was postoned (delay) till millennial, because Jews rejected Christ as King.
But, the kingdom was already brought by Jesus Christ.
In Matthew 4:17 tellsus, when after Jesus was baptized, and fasted for 40 days. He began to preach and he said, "Repent: for the kingdom of heaven is AT HAND." My understand what He means. He commands them to repent sins, for the kingdom of heaven is now at present.
Clear, Christ already bring kingdom to Israel. But most Jews and Pharisees were blind and reject him.
Does, Christ postponed the kingdom wait till millennial, because they reject him?
No. He already bring it to Israel. And the kingdom was start with in Jerusalem. When the Holy Spirit poured upon disciples on Pentacost Day of Acts chapter 2. They spread the kingdom over the world from Jerusalem.
We already have kingdom within us.
Kingdom is all about Jesus Christ and gospel. Kingdom is not about political or government as fansasty dream.
Kingdom is spiritual right now.
When Jesus comes again, kingdom shall become visible will be on new earth, and we shall reign with Christ forever and ever.
In Christ
Rev. 22:20 -Amen!