The parable usually known as 'The workers in the vineyard' in Matthew 20: 1-16 is a strange tale. It seems to go against the principle of fairness – and it turns out that this is the point. And it turns out too that as well as being about God's generosity, it is about economics and justice.

It's one of the parables Jesus tells to illustrate what the kingdom of heaven is like. A landowner hires men to work in his vineyard early in the morning and agrees to pay them the standard wage. He goes back a few hours later and hires more, promising to pay 'what is right'; then again a few hours later; and then again just before the end of the day.

When the time comes to pay the men, they all get the same – starting with those who came last. Not surprisingly, those who'd worked all day aren't impressed. But the landowner rebukes them: 'Don't I have the right to do what I want with my own money? Or are you envious because I am generous?'

In his book Jesus Through Middle Eastern Eyes, Kenneth Bailey draws out the oddities of the story. Any landowner would know how many men he needed to work his land for the day; he would have no need to go back for more.

Bailey writes of his own experience of living in Jerusalem, where unemployed Palestinians would gather near the Damascus Gate in hopes of work. 'I usually looked the other way when I passed, trying not to think about the humiliation those young men suffered and the quiet desperation that their presence reflected,' he says. But they, he notes, were gone by noon – in Jesus' story, the men were still there at the end of the day, because 'no one has hired us'.

Rather than humiliate them in their own and their families' eyes by giving them charity, however, he gives them what they needed – a job.

And Bailey also notes the order in which they're paid. If the first-comers had been paid first they would have left happy, and so on down to the last-comers. But the master wants everyone to see what he has done – perhaps so their characters can be tested and exposed. As Bailey says: 'The story focuses on an equation filled with amazing grace, which is resented by those who feel that they have earned their way to more.'

So the story is about God's gracious generosity expressed in a very practical way. It's been interpreted as referring to the first of Jesus' disciples and those who came later; as the Pharisees who worked all day in the heat of the sun before Jesus' disciples came in at the last minute; or even as a picture of the Jews and the Gentiles.

But it also speaks to us of work – why it matters, how workers should be treated and how employers should be generous. It's a warning against jealousy and legalism.

And most of all it's a picture of God's enduring love: the landowner makes the journey to and from the vineyard again and again, deliberately seeking out those who are lost and helpless, treating them with respect and giving them honourable work. In Jesus' parable, they can go home with their heads held high. They have been given not what they deserved, buy what they needed.  

Follow Mark Woods on Twitter: @RevMarkWoods