You see, the kingdom of God is not a physical place like a country or a city. In fact, every location or place is owned by Supreme Being so everything is all part of God’s kingdom from a location-sense.
But the physical world is the place of consequences: Where there is a consequence to every action performed with a self-centered motive ("as you sow, so shall you reap"). The spiritual world is not like the physical dimension.
Unfortunately, many look at the the spiritual world in this way - that it is like graduating from high school and going to college - and higher grades in high school guarantee placement in college.
The spiritual world does not have these characteristics. Yes, the spiritual world is also a dimension, separate from the physical world. But the physical world is also part of the kingdom of God. The spiritual world is quite simply, the dimension of love and humility - whereas the physical world is the dimension of self-centeredness.
The spiritual realm is where the key element is ones loving service relationship with God. There are no favorites. Just love. The Supreme Being loves each and every one of us unconditionally - regardless of what we have done or achieved. Thinking that God loves one of us more than another would be like asking a father which of his sons he loves more.
The spiritual world is where each of person takes shelter of God and exchanges love with Him - and the only qualification is to humbly accept His unconditional love.
Herein lies the secret of the parable. Many who read this parable of Jesus might focus upon the people actually working in the vineyard - and the fact that some worked all day and others worked for a few hours.
But the key to the parable is actually the relationship between the vineyard owner and each laborer:
"Why have you been standing here all day long doing nothing?"
"Because no-one has hired us," they answered.
"You also go and work in my vineyard." The vineyard owner is showing his mercy on the workers. He is recognizing their plight of not having any work - and thus money. They had the same needs the first group had, in that they needed to earn a living. So the vineyard owner’s focus was upon what their need, not how much they will work.
In the same way, some sectarian institution members might think, ‘if I am good and go to church every Sunday, I will certainly go to heaven.’ So while they are going to church every Sunday, they are feeling like they are racking up the church hours - qualifying for their entrance into the spiritual world.
Meanwhile, a humble person who never went to church looks up to the sky one day, falls to his knees and simply says in a humble and sincere prayer to God: “Oh compassionate God, I have no qualifications. I have sinned. I have nothing more to achieve. I simply want to come to love and serve You. Please help me.”
This one simple prayer, said with sincerity and humility, will in effect, move this person into immediate qualification to return to the spiritual world - maybe even ahead of the person who went to church every Sunday and sat in the pews for many years. This is because of the need for a relationship with the Supreme Being. Despite all the church sessions, the church-goer still has the same need for having a relationship with the Supreme Being. There is no difference between the two in terms of need.
Consider this parable in light of a person who spurns a relationship with another - say a person who runs off with another woman. What would be their qualification for returning to that relationship later? Would the spurned lover take the dodger back once flowers had been sent for five days in a row? Not necessarily. However, if the dodger approached with humility and sincerity, asking with an apologetic heart, the situation might change instantly, regardless of how many flowers were sent.
We can offer another analogy to illustrate this: Let’s say that we received two phone voicemails one day. One was from a person we talk to every day, and they chattered on about their day. The other was from a long lost friend we hadn’t talked to in twenty years and their voice mail talked about how much they missed us. Which of the two would we call back first?
(For a translation of Jesus' statements from the Book of Matthew without institutional sectarian influence, see the Gospels of Jesus - translated from the original Greek texts.)