Jesus answered, “My kingdom is not of this world. If my kingdom were of this world, my servants would have been fighting, that I might not be delivered over to the Jews. But my kingdom is not from the world.”- John 18:36
One of the most prominent themes throughout the Bible is the kingdom of God. It is impossible to form a theology of the kingdom of God solely based on John 18:36. Of course, the context of this verse needs to be taken into account as well. Regarding the kingdom, Israell’s existence and self-understanding was formulated from God’s covenant with Israel and Israel’s servant to God the King. Israel is the people of the king, and the Holy land is the land of the king’s rule. Biblical scholar J. Julius Scott Jr. has noted that in the ancient world, “kingdom” referred to “lordship,” “rule,” “reign,” or “sovereignty,” rather than simply a geographical location. Scott asserts “sovereignty (or rule) of God” would be a better translation than “kingdom of God,” since such a translation denotes God’s sphere or influence or control and includes any person or group who, regardless of their location, acknowledge His sovereignty. Therefore, this is why I generally use the phrase “reign of God,” rather than “kingdom of God.”
Alvin McClain offers three elements to a biblical definition of kingdom: First, there is a ruler with adequate authority and power; Second, a realm of subjects to be ruled; Third, the actual exercise of the function of the rulership. God’s kingdom is also called the kingdom of heaven (Matt 3:2;10:7), My Father’s kingdom (Matt 26:29), the kingdom of God’s dear Son (Col 1:12).
The term “kingdom of God” is absent from the Tanakh (the Old Testament). However, the God of Israel is identified as King: (1 Samuel 12:12; Psalm 24:10; Isa 33:22; Zeph 3:15; Zech 14:16-17), as ruler over Israel (Exod 15:18; Num 23; 21; Deut 33:5; Isa 43:15), and ruler over the entire creation (2 Kings 19:15; Isa 6:5; Jer 46:18; Psalm 10; 47:2; 93; 96:10; 145:11,13). The God of Israel also possesses a royal throne (Psalm.9:4; 45:6; 47:8; Isa 6:1; 66:1; Ezek 1:26); His reign is ongoing (Psalm10:16; 146:10; Isa 24:23), and rule and kingship belong to Him (Psalm 22:28). Bruce Waltke notes that the phrase “kingdom of the Lord” occurs in various forms and in only fifteen isolated texts (Ps.22, 103, 145; once in Obadiah; four times in Chronicles; and seven times in Daniel).  In the face of human rebellion and sin, God continued to assert His kingship and He continued to use Israel as a vehicle for the kingdom. We see in the Tanakh that in an eschatological sense, God’s sovereignty is not universally accepted, but it will happen in the future (Zech 14 1-9; Dan 7:13-14; 2 Sam 7:11-12; 16-17; Matt 19:28).
Jesus as the Inaugurator of the Reign of God: The Actions of the King
On point that is generally agreed on by all scholars is that the central message of Jesus was about the kingdom of God. He preached the arrival of the messianic age and its activity of deliverance, contrasting the greatness of the kingdom era with the era of John the Baptist, which had now seemingly passed (Luke 4:16-30; 7:22-23). In the New Testament, the Greek word for kingdom is “basileia,” which denotes “sovereignty,” “royal power,” and “dominion.” The references to the word “kingdom” can be seen in two classes: First, it is viewed as a present reality and involves suffering for those who enter into it (2 Thess. 1:5). Second, the kingdom is futuristic and involves reward (Matt 25:34), as well as glory (Matt 13:43).
The kingdom theme in the New Testament is part of the great cosmic battle and a reversal against sin and Satan. It is also the kingdom over which Jesus is currently ruling (1 Cor. 15:25; Rev 1:5-6) and is also tied to the ultimate realization of the kingdom in 1 Corinthians 15:26-28, where Paul describes the ultimate giving over of this same kingdom to the Father at the end.The New Testament authors identify Jesus in God’s presence and at His right hand (Acts 2:24-33; 5:31; 7:55-56; Eph.1:20-21; Col. 3:1; Heb. 1:3; 8:1; 10:12; 12:2; 2 Peter 3:22). By participating in God’s rule, Jesus is able to place all things in subjection under His feet. This theme, seen in the following New Testament passage exhibits that in early Jewish monotheism Jesus came to be recognized as ruling the cosmos from heaven: “Far above all rule and authority and power and dominion, and every name that is named, not only in this age but also in the one to come. And He put all things in subjection under His feet” (Eph. 1:21-22).
The Davidic King
While God promised that Israel would have an earthly king (Gen. 17: 6; 49:6; Deut.17: 14-15), the Davidic covenant established David as the king over all of Israel. Under David’s rule, there was the defeat of Israel’s enemies, the Philistines. David also captured Jerusalem and established his capital there (2 Sam. 1-6). As seen in 2 Sam. 7:1-4, David wanted to build a “house” (or Temple) for the Lord in Jerusalem. God’s response to David was one of rejection. However, God did make an unconditional promise to raise up a line of descendants from the house of David that would rule forever as the kings of Israel (2 Sam. 7:5-16; 1 Chr.17:7-15; Ps.89:28-37). The desire for the restoration of the Davidic dynasty became even more fervent after the united kingdom of the Israelites split into two kingdoms, Israel and Judah, at the time of King Rehoboam.
In 2 Samuel 7:12-17, the immediate prophecy is partially fulfilled in David’s son Solomon. However, the word “forever” shows there are future descendants to come. God promised David that his “seed” would establish the kingdom. The grant that David’s house would rule God’s kingdom forever lays the foundation of the messianic hope. J.J.M. Roberts says, “The claim that God had chosen David and his dynasty as God’s permanent agent for the exercise of divine rule on earth was the fundamental starting point for the later development of the messianic hope.” Isaiah 9:2 speaks of the Davidic Son as a light to the nations. This Davidic Ruler is repeatedly characterized as demonstrating justice and righteousness. Isaiah 11:2 speaks of the Spirit of God resting on this Davidic Ruler who brings wisdom and understanding to his people. Ezekiel 34-36 prophesies of a Davidic ruler as not only exercising his authority over the flock but also as mediating the cleansing work of the Spirit. 
Geza Vermes, a Jewish scholar, says that one of the best resources that speak to the messianic expectation of the time of Yeshua is found in The Psalms of Solomon. The Psalms of Solomon is a group of eighteen psalms that are part of the Pseudepigrapha which is written 200 BC to 200 A.D. Even though these works are not part of the Protestant Canon they are dated just before or around the time of Jesus. Therefore, they help provide the historian with valuable information into the Jewish religious life and thinking patterns at the time of Jesus. In it, there are two passages about a righteous, ruling Messiah:
“Taught by God, the Messiah will be a righteous king over the gentile nations. There will be no unrighteousness among them in his days, for all shall be holy and their king shall be the Lord Messiah. He will not rely on horse and rider and bow, nor will he collect gold and silver for war. Nor will he build up hope in a multitude for a day of war. The Lord himself is his king, the hope of the one who has a strong hope in God. He shall be compassionate to all the nations, who reverently stand before him. He will strike the earth with the word of his mouth forever; he will bless the Lord’s people with wisdom and happiness. And he himself will be free from sin, in order to rule a great people. He will expose officials and drive out sinners by the strength of his word.” (Psalms of Solomon 17.32-36)
“Lord, you chose David to be king over Israel, and swore to him about his descendants forever, that his kingdom should not fail before you. Undergird him with the strength to destroy the unrighteous rulers, to purge Jerusalem from the gentiles…..to destroy the unlawful nations with the word of his mouth…He will gather a holy people who he will lead in righteousness; and he will judge the tribes of his people…He will not tolerate unrighteousness (even) to pause among them, and any person who knows wickedness shall not live with them… And he will purge Jerusalem (and make it) holy as it was from the beginning.” (Psalms of Solomon 18:4,22,26,27,30)
We see the fulfillment reached its completion in the Messiah, both son of David and the one greater than David (Psalm 2 and Psalm 110). As stated in the New Testament, Jesus the Messiah, is the “seed of David,” sent by God to restore God’s kingship over mankind (Matt. 1:1; Acts 13:23; Rom. 1:3,4; Rev. 22:16). As it says in Luke 1:32-33, “He shall be great, and will be called the Son of the Most High; and the Lord God will give Him the throne of His father David; and He will reign over the house of Jacob forever; and His kingdom will have no end.”
The Reign of God: “Already, But Not Yet”
In relation to the kingdom of God theme, one of the most debated issues in biblical scholarship is whether Jesus actually offered the earthly, national, or political aspect of the kingdom of God. A look at the content of Jesus and John the Baptist show the kingdom is the central theme of their message: (1)“Repent, for the kingdom of heaven has come near”(Matt.3:2);(2) “Repent, the kingdom of heaven has come near”(Matt. 4:17); (3) “The kingdom of heaven has come near”(Matt 10:7). One of the crucial issues in this debate is the meaning behind the Greek word “engizo” which can mean “has already arrived” or “has drawn near.”  According to New Testament scholar Scot McKnight, it is best taken to mean “has drawn very near but is not yet come.”  To support this view, McKnight says there are passages such as Matt. 21:1, where the travelers have drawn near to Jerusalem but are still in Bethphage (thus “have drawn very near”); in Matt. 21:34, the time for the harvest has drawn near but has not yet arrived; and in Matt. 26:45, the hour of Jesus’ death has drawn so near that its impact is now being felt, but it remains in the future. Therefore, while the kingdom is now operative in some regards, it still has a futuristic aspect in which Israel will be all that God has purposed it to be. 
In looking at the Messianic task of Jesus, His work is broken up into a series of stages:
1. The Messianic King was presented at John’s baptism (Matt. 3:1-17). In other words, this is when He was consecrated for the messianic task.
2. The Messianic King presented His miracles as evidence of His messiahship: (Matt. 11:4–6; see also Lk. 7:22). The prophet Isaiah spoke of a time where miraculous deeds would be the sign of both the spiritual and physical deliverance of Israel (Is.26: 19; 29:18-19; 35:5-6; 42:18; 61:1).
2. The Messianic King was crucified (Isaiah 52: 13-53: 1-12). He then rose from the dead and ascended to the Father (1 Cor.15:1-17; Acts 1: 9-11).
3. Jesus’ current messianic work is a priest-advocate (1Jn. 2:2; Hebrews 7:1-27).
4. One day, Jesus will return and establish the earthly, national aspect of the kingdom of God. (Is. 9:6; Amos 9:11; Dan. 2:44; 7:13-14; 27; Is. 11:11-12; 24:23; Mic. 4:1-4; Zech.14:1-9; Matt. 26:63-64; Acts 1:6-11; 3:19-26). In other words, one day the Messiah will be King over His people (Matt. 19:28).
The reign of God is one of the most pertinent themes in biblical theology. God has extended His mercy and grace to the human race by allowing us to glance at the role of the kingdom of God in His plan for the redemption of the entire world. God took the initiate by revealing to mankind a fuller part His kingdom program through the ministry of Jesus of Nazareth. Jesus’ miraculous deeds, healings, and power over nature as well as His role as a Suffering Servant was another stage of inaugurating the kingdom of God. Jesus also fulfills the role of the inaugurator of the kingdom of God by being honored and demonstrating the authority to execute judgment. Jesus currently rules over the cosmos at the right hand of the Father (Acts 2:24-33; 5:31; 7:55-56; Eph.1:20-21; Col.3:1; Heb. 1:3; 8:1; 10:12; 12:2; 2 Peter 3:22). Jesus, being the divine Messiah exhibits the same attributes as the God of Israel. One day, Jesus will return to fulfill the promise of completing the earthly aspect of His kingdom work. May all of us as wait with eager anticipation. As the Apostle Peter said,
But the day of the Lord will come like a thief. The heavens will disappear with a roar; the elements will be destroyed by fire, and the earth and everything in it will be laid bare. Since everything will be destroyed in this way, what kind of people ought you to be? You ought to live holy and godly lives as you look forward to the day of God and speed its coming. That day will bring about the destruction of the heavens by fire, and the elements will melt in the heat (2 Peter 3:10-12).
 J. J. Scott Jr, Customs and Controversies: Intertestamental Jewish Backgrounds of the New Testament (Grand Rapids: Baker Books, 1995), 297.
 See Alvin J. McClain, The Greatness of the Kingdom (Winona Lake, IND: BHM, 1974).
 David Baker, Looking Into The Future: Evangelical Studies In Eschatology (Grand Rapids, Baker Books, 2001), 15.
 W.E. Vine, Merrill F Unger, and William White Jr., Vine’s Complete Expository Dictionary Of Old And New Testament Words (Nashville: Thomas Nelson Publishers, 1985), 344.
 J.J.M. Roberts, “In Defense of The Monarchy: The Contribution of Israelite Kingship to Biblical Theology” in Ancient Israelite Religions: Essays in Honor of Frank Moore Cross ed. Patrick D. Miller Jr. Paul D. Hanson, and S. Dan McBride (Philadelphia, Fortress, 1987), 178.
 Baker, 348.
 Geza Vermes, Jesus the Jew. A Historian’s Reading of the Gospels ( New York. Macmillan Publishing Co. 1980), 251
 See Scot McKnight. A New Vision For Israel: The Teachings of Jesus in National Context(Grand Rapids; Eerdmans, 1999), 70-155.