When Was the Kingdom of God Established?

[Desertsrose]

Here's a great article from got questions dot org.


The phrase gospel of the kingdom and references to “the kingdom of God” and “the kingdom of heaven” are used repeatedly in connection with the Lord Jesus and His work on earth. The word gospel simply means “good news,” and the term translated “kingdom” is the Greek word basileia, which means “the realm in which a sovereign king rules.” Throughout the New Testament, the word kingdom consistently refers to the rule of Christ in the hearts of believers, since, for the time being, Christ’s kingdom is not of this world (John 18:36).


When Jesus began His three-year earthly ministry, He preached that “the kingdom of God is near” (Matthew 4:17; Luke 10:9). Mark 1:14–15 gives a concise description of Jesus’ primary focus during His time on earth: “Now after John was arrested, Jesus came into Galilee, proclaiming the gospel of God, and saying, ‘The time is fulfilled, and the kingdom of God is at hand; repent and believe in the gospel.’” When asked to define His kingdom, Jesus explained it this way: “The kingdom of God is not coming in ways that can be observed. . . . The kingdom of God is in the midst of you” (Luke 17:20–21). Romans 14:17 says that the kingdom of God is a matter “of righteousness and peace and joy in the Holy Spirit.”


The gospel of the kingdom is the good-news message of repentance, redemption, and restoration offered by God to all who will receive Christ. Those who accept this offer become part of His eternal kingdom (John 1:12). Those who choose to remain in their sin cannot be a part of this kingdom (1 Corinthians 6:9–10; Galatians 5:19–21). Although grace makes this offer available to anyone who will receive it, Jesus warned that it would be very difficult to enter His kingdom and few would do so (Matthew 7:14).

 

[Desertsrose]

Here's the other half.

The gospel of the kingdom is the news that there is freedom from our slavery to sin if we will repent and turn to God (Romans 6:18–19). Our Redeemer has come, but it is difficult to enter God’s kingdom, not because God requires impossible standards for us, but because we do not want to repent and change. We tend to love the darkness more than the Light (John 3:19). Many would rather cling to their old sinful identities than allow Jesus to create them anew (2 Corinthians 5:17).

Those who receive the gospel of the kingdom become citizens of heaven and are freed from bondage to this world (Galatians 4:3–9). Second Corinthians 5:20 refers to God’s children as “ambassadors” for our heavenly Father. Just as an earthly foreign ambassador retains his national identity when representing his country in another, the spiritual ambassadors of God’s kingdom owe their allegiance to God even as they reside in this world. We must follow our heavenly Father’s code of conduct while sojourners on earth. We need not conform to this world’s habits, values, and lifestyle, because this is not our home (Romans 12:1–2; 1 John 2:15–17).

Jesus said, “My kingdom is not of this world” (John 18:36). So, although we must live here until God calls us home, we are not to live for ourselves or according to this world’s value system. Those who have been bought by the blood of Jesus have been given the right to live according to God’s value system. Citizens of the kingdom of God live here on assignment from our Father the King. Living with a kingdom mindset empowers us to make wiser decisions as we invest our lives in furthering the gospel of the kingdom.

 

[J7]

That's fine, but he is describing the Kingdom Of Heaven, not the Kingdom Of God.

The Kingdom of God did not arrive until the Old Covenant had finished

Luke 21:31
So likewise ye, when ye see these things come to pass, know ye that the kingdom of God is nigh at hand.