Matthew 20:13-14- What's Fair?

Matthew 20:13-14 " But he replied to one of them, ‘Friend, I am doing you no wrong. Did you not agree with me for a denarius? Take what belongs to you and go...'" commentary- A land owner hires extra workers late in the day and promises to pay them. When the end of the day came, the men who started work early got their share that they agreed upon. Yet, the ones who only worked an hour due to being hired later also received the same pay as those who worked a full day. 

Those that worked longer were upset thinking that they should have more than the other who came late. The landowner made no extra promises, he only followed what he said he would do. 

I compare this to the kingdom of Heaven. I have heard numerous arguments from unbelievers who think that it isn't "fair" that one can live a life of sin and still get their sins forgiven when others asked for forgiveness a long time ago. God doesn't operate on what's fair, but He operates on being true to His word. If he says it, it is true. It is not a scale that we use to rank who is the greatest in the kingdom of Heaven (see Matthew 18:1-6). God forgives and knows your heart, it is not up to you to try to take on a role (God or in this chapter's case the landowner) that is not assigned to you. Do your part.