"In those days came John the Baptist, preaching in the wilderness of Judaea, And saying, Repent ye: for the kingdom of heaven is at hand." -Matthew 3:2
"Jesus came into Galilee, preaching the gospel of the kingdom of God, And saying, The time is fulfilled, and the kingdom of God is at hand: repent ye, and believe the gospel." -Mark 1:14-15
"And as ye go, preach, saying, The kingdom of heaven is at hand." - Matthew 10:7
The principles of dispensationalism, if accepted, would require us to reject John the Baptist and Christ as false prophets. If the Kingdom was not "at hand," not even close to it, if the time for the Kingdom was not fulfilled at that time, if the Kingdom was not to come for at least 2000 more years, then we have no choice but to reject them as false prophets.
Just what kind of people reject the New Testament teaching that Christ successfully brought in God's Kingdom? Well, the Pharisees rejected it. Christ told the Pharisees, in response to their objections and taunts, "But if I cast out devils by the Spirit of God, then the kingdom of God is come unto you." - Matthew 12:28
The Pharisees, like modern dispensationalists, rejected the Kingdom that Christ brought in, because it was not the earthly literal kingdom that the Pharisees wanted. "And when he was demanded of the Pharisees, when the kingdom of God should come, he answered them and said, The kingdom of God cometh not with observation: Neither shall they say, Lo here! or, lo there! for, behold the kingdom of God is within you." -Luke 17-20-21.
"Verily I say unto you, There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom." - Matthew 16:28. My question for dispensationalists who believe in the "deferred kingdom" and the 2000- year "parenthesis" in God's plan, forced on Him by mere mortal men - give us the names and current locations of those who heard Christ's word in Matthew 16:28 and who never died and are still alive today - presumably in old folks' homes somewhere.