We know from the information the kingdom/church was established in Jerusalem on Pentecost.
We can also see the numerous passages speaking of the kingdom being "at hand." Even just before the cross, on the cross with the thief, and after the cross, we see several comments intimating that the kingdom is still yet future - pointing to Pentecost.
However, there are several passages which use the present tense concerning the kingdom:
Matthew 12:28 – “But if I cast out demons by the Spirit of God, surely the kingdom of God has come upon you.”
Matthew 21:31 – “Which of the two did the will of his father?” They said to Him, “The first.” Jesus said to them, “Assuredly, I say to you that tax collectors and harlots enter the kingdom of God before you.”
Matthew 23:13 - “But woe to you, scribes and Pharisees, hypocrites! For you shut up the kingdom of heaven against men; for you neither go in yourselves, nor do you allow those who are entering to go in.”
Luke 16:16 – “The law and the prophets were until John. Since that time the kingdom of God has been preached, and everyone is pressing into it.”
Luke 17:21 – “nor will they say, ‘See here!’ or ‘See there!’ For indeed, the kingdom of God is within you.”
Some cling to the present tense suggesting that folks were entering the kingdom prior to Pentecost. In fact, prior to the death, resurrection, ascension, glorification, His ruling as king, and even before His last Will and Testament.
What are your thoughts on this matter?
The terms "church" and "kingdom" are not referring to exactly the same thing. They overlap heavily, but they are not totally interchangeable.
The church refers to the body of people who have been called out of sin and the world. It translates the Greek word ekklesia which means "called out." Jesus declared that he would build an assembly of people who were exclusively his. "I also say to you that you are Peter, and upon this rock I will build My church; and the gates of Hades will not overpower it" (Matthew 16:18).
The kingdom refers to a spiritual place whose people are under the authority of God and where the laws of God are in force. "For the kingdom is the Lord's, and He rules over the nations" (Psalms 22:28). Notice that David writes about the kingdom as presently existing, but that is because God has always had authority over the world. This kingdom (this authority) was turned over to Jesus after his resurrection. "I kept looking in the night visions, and behold, with the clouds of heaven One like a Son of Man was coming, and He came up to the Ancient of Days and was presented before Him. And to Him was given dominion, glory and a kingdom, that all the peoples, nations and men of every language might serve Him. His dominion is an everlasting dominion which will not pass away; and His kingdom is one which will not be destroyed" (Daniel 7:13-14). What Christ received from the Father already existed. "And Jesus came up and spoke to them, saying, 'All authority has been given to Me in heaven and on earth'" (Matthew 28:18). One day, Christ will return the kingdom back to the Father. "But each in his own order: Christ the first fruits, after that those who are Christ's at His coming, then comes the end, when He hands over the kingdom to the God and Father, when He has abolished all rule and all authority and power. For He must reign until He has put all His enemies under His feet" (I Corinthians 15:23-25).
Typically, when we talk about the kingdom, we are talking about those who accept God's rule and power of their lives. Thus, in the New Testament, the faithful in the church are in the kingdom. But it also means that the faithful in the past are also in the kingdom. "In that place there will be weeping and gnashing of teeth when you see Abraham and Isaac and Jacob and all the prophets in the kingdom of God, but yourselves being thrown out. And they will come from east and west and from north and south, and will recline at the table in the kingdom of God" (Luke 13:28-29).
Let's look at the verses you cited:
- In Matthew 12:38, Jesus cast out a demon, which the Pharisees claimed was by the power (or authority) of Satan. Jesus points out the unreasonableness of their claim and then states that if he is doing it by the authority of the Holy Spirit then the reasonable conclusion is that they are seeing signs of the long-awaited kingdom of the Messiah because Jesus is demonstrating the authority of the Messiah.
- In Matthew 21:31, Jesus is saying that the tax-gatherers and prostitutes are ahead of the Pharisees in line to enter the kingdom. That is, these sinners are closer to becoming a part of the kingdom than the Pharisees because they are willing to leave their sins and accept Christ's authority over them.
- In Matthew 23:13, "are entering" is not the same as saying they have entered. These people are making changes in their lives that are necessary in order to enter the kingdom. The Pharisees were hindering their changes.
- In Luke 16:16, the Old Testament was taught up until the time of John (Matthew 11:12-13). With the coming of John, a new Law, the Gospel of the kingdom of God has been preached (Mark 1:1; Matthew 4:17). While the Pharisees scoffed at the teachings, others have been eager to enter the kingdom. Jesus uses the imagery of a mob violently pushing its way through a door. Imagine the crowds pressing at the door of a Black Friday sale before the store opens. People are pushing for entrance into the kingdom, but they are wanting it to happen immediately. But it won’t happen until everything the Law stated was fulfilled (Matthew 5:18). There would be changes, but they would not come by the will of man (Psalm 102:26-27).
- In "Now having been questioned by the Pharisees as to when the kingdom of God was coming, He answered them and said, "The kingdom of God is not coming with signs to be observed; nor will they say, 'Look, here it is!' or, 'There it is!' For behold, the kingdom of God is in your midst"" (Luke 17:20-21), Jesus is saying that the long-awaited kingdom is not physically observed. It is a spiritual kingdom. The phrase translated "in your midst" or "within you" means something that is inside, within a person's reach, or in their midst. The kingdom was already becoming noticeable as people swung their allegiance to Jesus. The kingdom was forming in the hearts of people in the crowd. The Pharisees would realize this if they would accept who Jesus was, but they would not.
We tend to look at the coming kingdom as an on-off switch, but the gospels show that it was a development that took place over several years as the authority of Jesus was proven and accepted by people.
Thank you brother, Jeff!