what's Jesus saying?

So, what is Jesus trying to say here in this parable – you tell me in the comments...

Matthew 20

1 "For the Kingdom of Heaven is like the landowner who went out early one morning to hire workers for his vineyard.

2 He agreed to pay the normal daily wage and sent them out to work.

  3 "At nine o'clock in the morning he was passing through the marketplace and saw some people standing around doing nothing.

4 So he hired them, telling them he would pay them whatever was right at the end of the day.

5 So they went to work in the vineyard.

At noon and again at three o'clock he did the same thing.

  6 "At five o'clock that afternoon he was in town again and saw some more people standing around.

He asked them, 'Why haven't you been working today?'

  7 "They replied, 'Because no one hired us.'

  "The landowner told them, 'Then go out and join the others in my vineyard.'

  8 "That evening he told the foreman to call the workers in and pay them, beginning with the last workers first.

9 When those hired at five o'clock were paid, each received a full day's wage.

10 When those hired first came to get their pay, they assumed they would receive more.

But they, too, were paid a day's wage.

11 When they received their pay, they protested to the owner,

12 'Those people worked only one hour,

and yet you've paid them just as much as you paid us who worked all day in the scorching heat.'

  13 "He answered one of them,

'Friend, I haven't been unfair!

Didn't you agree to work all day for the usual wage?

14 Take your money and go.

I wanted to pay this last worker the same as you.

15 Is it against the law for me to do what I want with my money?

Should you be jealous because I am kind to others?'

  16 "So those who are last now will be first then, and those who are first will be last."