As usual, the answer can be found in the bible: 
Matthew 20
The Parable of the Workers in the Vineyard
1"For the kingdom of heaven is like a landowner who went out early in the morning to hire men to work in his vineyard. 2He agreed to pay them a denarius for the day and sent them into his vineyard.
3"About the third hour he went out and saw others standing in the marketplace doing nothing. 4He told them, ‘You also go and work in my vineyard, and I will pay you whatever is right.’ 5So they went.
"He went out again about the sixth hour and the ninth hour and did the same thing. 6About the eleventh hour he went out and found still others standing around. He asked them, ‘Why have you been standing here all day long doing nothing?’
7" ‘Because no one has hired us,’ they answered.
"He said to them, ‘You also go and work in my vineyard.’
8"When evening came, the owner of the vineyard said to his foreman, ‘Call the workers and pay them their wages, beginning with the last ones hired and going on to the first.’
9"The workers who were hired about the eleventh hour came and each received a denarius. 10So when those came who were hired first, they expected to receive more. But each one of them also received a denarius. 11When they received it, they began to grumble against the landowner. 12’These men who were hired last worked only one hour,’ they said, ‘and you have made them equal to us who have borne the burden of the work and the heat of the day.’
13"But he answered one of them, ‘Friend, I am not being unfair to you. Didn’t you agree to work for a denarius? 14Take your pay and go. I want to give the man who was hired last the same as I gave you. 15Don’t I have the right to do what I want with my own money? Or are you envious because I am generous?’
16"So the last will be first, and the first will be last."
