Christ related a parable to describe the kingdom of heaven, which is the church. The landowner, who represented God, went out early in the morning to hire laborers to work that day.
A day’s pay was a denarius or eternal life in heaven for a lifetime of work in the church.
Later in the morning, he saw others who were idle and hired them for “whatever is right.” These workers represented those who heard the gospel a little later in life and obeyed. At midday, mid-afternoon and even near the end of the day, he hired other laborers for the same wage. These represented individuals who had heard the gospel late in life and had obeyed.
Even though those who went to work early complained about all laborers receiving the same wage, God has promised an eternal reward for all who “hire” on as Christians and remain faithful throughout life. Notice that those who started working late in life had not been approached until then. They obeyed the call as soon as they heard it.