The Parable of the Eleventh Hour Worker
In Matt 19:16-22, Jesus tells us of a story of a rich young ruler who wanted Jesus to tell him "what good thing shall I do that I may have eternal life?". Jesus went on to described how he should keep the commandments and he claimed that he had done it all. Jesus finally told him to sell all his possessions, in which he responded with sorrow and went away. In Matt 19:23-27, the disciples were astonished at Jesus's conclusion of the rich young ruler by saying in verse 24, "it is easier for a camel to go through the eye of a needle than for a RICH MAN to enter the kingdom of God". Peter responded in verse 27, “See, we have left all and followed You. Therefore what shall we have?”. He wants to know what can he get by his sacrifice for following Jesus.
Matt 19:28-30 is interesting. Jesus went on to explain how the 12 places will be given to the 12 who followed him, obviously referring to the 12 Apostles who will judge the 12 tribes of Israel when Jesus comes back. And everyone who left their houses and family for the sake of the gospel will receive a hundredfold and inherit eternal life. From which he gave a quote at verse 30, " But many who are first will be last, and the last first"
He then went on in Matt 20:1-16 to tell a story of an owner of the Vineyard (usually referring to God the Father [CF Isaiah 5] ), who hired laborers for his vineyard early in the morning, third hour, sixth hour, ninth hour and eleventh hour. At the end of the day, the earlier workers who worked more received the same 1 denarius as the eleventh hour workers, they complained. The owner of the vineyard responded by saying, in verse 13,"‘Friend, I am doing you no wrong. Did you not agree with me for a denarius?" And again, this passage again ended with an inclusio with Matt 19:30, "So the last will be first, and the first last. For many are called, but few chosen."
Firstly, the reward of 1 denarius refers to eternal life (CF Matt 19:29). I believe the workers who came in at the earlier hours refers to Israel under the Law of Moses and 11th hours refers to believers after the Cross. Jesus was giving an illustration to his disciples on how those who are born again under the Grace of Jesus finished work receives the same eternal life as those who persevered by Faith while under the Law of Moses. There is nothing we can do to earn eternal life, any more than those who serve more or less. Hence the principal of equality lies in the phase "the last will be first, and the first last.".
Yet the author of Matthew did not stop there, but to further illustrate the greatness of serving in Matt 20:20-28.
"Yet it shall not be so among you; but whoever desires to become great among you, let him be your servant. And whoever desires to be first among you, let him be your slave— just as the Son of Man did not come to be served, but to serve, and to give His life a ransom for many.”" - Matt 20:26-28
Eternal life cannot be earned by working more. It is about God's Grace towards imperfect people who are willing to walk in faith and serve him. Eternal rewards (1 Cor 3:5-16) however, is a different topic altogether.