The parable of the workers in the vineyard is about several workers who are hired by a man who owns a vineyard, over different periods of time. At the end of the day the people who are hired first expect to be paid more than those hired later. But, the man pays all of the workers equally.
This parable is significant because it is as representation of the fact that you can become a good person at any point in your life and you will receive equal treatment in heaven as someone who has turned their life around very recently. The workers, who were picked up earlier and were saved from unemployment, represent those who have been good for their entire life. Those picked up later; represent the ones who have turned it around later in life. No matter, who you are as long as you die as a good person who did good deeds than you will be accepted into the kingdom of heaven and be given equal treatment.
As a recurring theme in the parables, we are taught through this story that God cares that we are a good person when we die as opposed to throughout our entire life. God appreciates when we admit that we’ve made mistakes and as soon as we do that he will accept us in heaven. When someone decides to change their ways, which is enough for God as he is a forgiving person.