Romans 14:16-17 Therefore do not let your good be spoken of as evil; for the kingdom of God is not eating and drinking, but righteousness and peace and joy in the Holy Spirit.
Preterist amillennialists fail to recognize the definition of the spiritual kingdom of God as defined by the apostle Paul. Additionally, they often will disagree amongst themselves.
BIBLICAL STUDIES IN FINAL THINGS - William E. Cox
Page 117: Another example of misapplication of Scripture on this doctrine would be our Lord's prediction of his transfiguration. In Matthew 16:28 we find these words: "Verily I say unto you, there are some of them that stand here, who shall in no wise taste of death, till they see the Son of man coming in his kingdom." Although many apply this prediction to the second advent, the verses which follow immediately after give the true fulfillment of the prophecy. For Matthew goes on to say that "after six days Jesus . . . was transfigured before them . . ." (Matt. 17:1, 2).
THE LAST DAYS ACCORDING TO JESUS - R.C. SPROUL
Page 53: This immediately calls attention to another of Jesus' time-frame references in the Gospels: "For the Son of Man will come in the glory of His Father with His angels, and then He will reward each according to his works. Assuredly, I say to you, there are some standing here who shall not taste death till they see the Son of Man coming in His kingdom." (Matt. 16:27-28)
Matthew declares that some who were in Christ's immediate presence as he was speaking ("some standing here") would not "taste death" before they would "see the Son of Man coming in His kingdom." The term coming that appears in the Greek text of Matthew 16:28 is not the word parousia. Nevertheless, Jesus does speak of a "coming" of the Son of Man.
Page 54: That events like the transfiguration and resurrection are manifestations of the coming of God's kingdom is hardly in dispute among most New Testament scholars. The only problem with this linkage is the time-frame reference. In this case, however, it is not that the time-frame is too remote or temporally disconnected from the prediction. Rather it is that the time-frame reference is too near. In Mark's Gospel the account of the transfiguration is set in the very next verse, and this verse begins with a specific time reference: "After six days . . ." (9:2). If Jesus' prediction to the disciples is fulfilled within one week (or a few weeks, if the prediction refers to the resurrection, ascension, or Pentecost), why would he specify that these events will occur before "some (of them) standing here . . . will . . . taste death" (9:1)?
Page 55: If the Olivet Discourse refers primarily to events surrounding the destruction of Jerusalem and if the word generation refers to a forty-year period, then it is possible, if not probable, that Jesus' reference to his coming in Matthew 16:28 refers to the same events, not to the transfiguration or other close-at-hand events.
Since the spiritual kingdom of God is righteousness, peace, and joy in the Holy Spirit, then it began for us Christians at Pentecost with the outpouring of the Spirit. (Acts 2:4) The spiritual kingdom of God will be internalized into a true believers life. (1 Corinthians 3:16; Colossians 1:27) In order to be in the spiritual kingdom of God, a person must ask or receive Jesus Christ into their life through simple childlike faith and trust. (Mark 10:14-15; John 1:12-13) Manifestations of the spiritual kingdom of God in a person should be obvious to everyone. (Galatians 5:22-23) "But the fruit of the Spirit is love, joy, peace, long-suffering, kindness, goodness, faithfulness, gentleness, self-control. Against such there is no law."