The earthly kingdom of Israel is not "the Kingdom of God." The Jews of Christ's day misunderstood this as many do today by looking for an earthly kingdom of God in downtown geographic Jerusalem in the future.
Christ predicted, "Assuredly, I say to you that there are some standing here who will not taste death till they see the kingdom of God present with power." (Mark 9:1)
The time-frame is limited for the fulfillment of this prophecy - some standing there may be dead by the time this event occurs while some will not have died. This would place the time of this prediction to around, and before, all His contemporaries pass away. IOW, this contemporary generation will not pass away till the kingdom of God is seen/realized. Jerusalem's destruction in 70 AD fits this prediction with respect to both time and power - for He said that it would be attended with power.
Jerusalem's destruction in 70 AD was predicted by Christ as well. In the Olivet Discourse Christ associates the coming of the kingdom of God with this predicted destruction of Jerusalem. (Luke 21:31&32) Prior to this Discourse Christ pronounced several woes on that generation and the wrath which would shortly come upon them. (Matt. 23) Paul later wrote that this wrath has come upon them - "who killed both the Lord Jesus and their own prophets, and have persecuted us; and they do not please God and are contrary to all men, forbidding us to speak to the Gentiles that they may be saved, so as always to fill up the measure of their sins; but wrath has come upon them to the uttermost." (1 Thess. 2: 15&16) "All these things" are said to be the judgments Christ and the prophets of the OC said would befall them for their continued obstinacy. (Matt. 23:36) For the gospel of the kingdom was first preached to them and they refused it collectively as a nation - bringing judgment on themselves. So, the kingdom of God which was preached to them first was taken from them and came to others. (Matt. 21:43)
The Son of Man came in judgment to that OC nation at the end of that age as He predicted. For that was the question: "what will be the sign of your coming and of the end of the age?" (Matt. 24:1) The kingdom of God then went to the whole world beginning the 'times of the Gentiles.' Thus, the Son of Man came in judgment and the kingdom of God came to others as predicted by Christ marking the end of one age and the beginning of another age. (1 Cor. 10:11)
Pentecost came with power but occured too early to fulfill Mark 9:1. Yet, it pointed to an even earlier prophecy concerning the kingdom of God.
"Therefore, when they had come together, they asked Him, saying, 'Lord, will You at this time restore the kingdom to Israel?'" (Acts 1:6) Christ had just taught them things concerning the kingdom of God and yet they were still incorrectly looking for a temporal fulfillment. (cf. Jn. 18:36) We see a reference to power in Christ's answer, "It is not for you to know times or seasons which the Father has put in His own authority. But you shall receive power when the Holy Spirit has come upon you; and you shall be witnesses to Me in Jerusalem, and in all Judea and Samaria, and to the end of the earth." (Acts 1:7-8)
After Pentecost these same ones, who were confused about the kingdom of God prior to this, preached, reasoning and persuading, about the things concerning the kingdom of God. (Acts 8:12; 19:8; 28:23,31) In fact, at Pentecost Peter's words recall Nathan's prophecy about the everlasting kingdom in 2 Samuel 7:11-17. Nathan had predicted that God would build this house while David sleeps with his fathers - i.e. before David's bodily resurrection. (see Acts 2:29-36) Nathan predicted:
1) It is with A Seed/Offspring.
2) It will be established forever.
3) He will build a house for God's name.
4) His throne will be established forever.
Nathan's prophesy has been fulfilled in the natural in Solomon and in the spiritual in Christ. First comes the natural then the spiritual. (1 Cor. 15:46)
Fulfillment of Nathan's prophecy concerning the everlasting kingdom in the New Covenant in Christ:
1) Luke 2:10&11; Ro. 1:3 - Christ was born of the seed of David according to the flesh. A Seed/Offspring
2) Mark 1:14-15; Jn 3 - Christ's kingdom was not of this world but spiritual. Its entrance is by spiritual rebirth. His kingdom has been established forever. "the inhabitants of Jerusalem" are those who now "have come to Mount Zion and to the city of the living God, the heavenly Jerusalem, to an innumerable company of angels," (Heb. 12:22), "the Jerusalem which is above" (Gal. 4:26).
3) 1Tim.3:15, 1Pe. 2:5 - not a house of clay or wood but lively stones, each of us, the elect, being fitted together to form His spiritual house, "Whose house we are" (Heb. 4:6).
4) Luke 1:32 - the throne of His father David, Hebrews 10 - He sat down at the right hand of the Father. The last enemy to be destroyed will be death. (1Cor. 15) He. 1:8 - "But to the Son He says: 'Your throne, O God, is forever and ever; A scepter of righteousness is the scepter of Your Kingdom.'"
What is future?
John, in Revelations, saw saints as 'souls' in heaven which implies that these saints do not have glorified bodies yet - the first resurrection - to be absent from the body is to be present with the Lord. The resurrection of our bodies is still to come. (1 Cor. 15, Rev. 20) There is no record of a resurrection of the dead and a rapture of the living having occurred yet. The graveyards still contain bodies. Paul taught that the resurrection of our bodies would be like that of Christ's. When they came to the tomb where Christ was buried and the stone had been rolled away and they looked inside and did not see a physical body. Also, He appeared to the disciples and was seen by them and Thomas touched Him.
The great white throne judgment is still future together with His appearing at the end of this age. "I charge you therefore before God and the Lord Jesus Christ, who will judge the living and the dead at His appearing and His kingdom:" (2Ti 4:1) There is an already and a not yet aspect of His appearing and kingdom. Already the Son of Man appeared in judgement and His kingdom came to the world in 70 AD - the ~present wrath~ in 1 Thess. 2:16. The not yet part is that He will appear again before the ~future wrath~ in 1 Thess. 1:10. This future wrath and appearing will be at the end of history. (2 Pe. 3:10-13) We are already citizens of this kingdom and it is an inheritance that we will realize later.
"Then comes the end, when He delivers the kingdom to God the Father, when He puts an end to all rule and all authority and power." (1 Cor. 15:24)