The answer is: Some had worked less hours for the same pay

Matt 20:1-16 - Such is the kingdom of heaven. Some may labour in the Lord's vineyard for longer, but the reward is the same.

In the parable of the workers in the vineyard, Jesus cleverly provides insight into fairness, expectations, and divine grace. When some of the laborers who-toiled longer found out they were receiving the same wage as those who worked fewer hours, it sparked feelings of dissatisfaction and envy. Their protest, questioning whether it was fair that those who worked less earned the same pay, highlights a common human trait—comparing ourselves to others.

What is fascinating here is that the vineyard represents more than just a business; it symbolizes the Kingdom of Heaven, where different people come at various times in their lives, to join in contributing to a greater purpose. Throughout the Bible, especially in the Gospels, themes of inclusion and unexpected mercy are recurrent. For instance, think of the lost son who returned to his father after squandering his wealth, receiving an unexpectedly warm welcome—that grace is what ties these stories together.

Interestingly, in the Jewish understanding of work and reward, people often associated God's blessings with one's labor. Here, when all recipients receive the same reward regardless of hours worked, Jesus confronts traditional views and challenges the notion of meritocracy. It invites reflection on the universality of God's grace, reminding us that it's about being part of the kingdom—essentially reminding all that Gentile or Jew, early riser or latecomer, can all partake in divine generosity. Isn’t it refreshing to imagine a world where everyone is invited to share in love and grace, just for being?