Luke 20:17
And he beheld them, and said, What is this then that is written, The stone which the builders rejected, the same is become the head of the corner? And he beheld them, and said, What is this then that is written, The stone which the builders rejected, the same is become the head of the corner?
This question closes the parable of the vineyard, which pictures the first coming of Christ and the treatment He received. God first sent His prophets to ancient Israel, and when their message was not heeded He sent His own Son as a last resort to reach hearts and turn them back to God. The sending of the servants and then the son has this meaning, that the final mission was to turn the people to God after the earlier calls were ignored.
The builders who reject the stone are the religious leaders, the priests and rulers and Jewish leaders. They are also the unfaithful husbandmen and vineyard tenants in the parable. The stone is Christ, rejected by the builders yet made the cornerstone and chief cornerstone. He is the foundation of the Christian church, and their rejection does not prevent Him from becoming that foundation. The rock on which the church is built is Christ, not Peter. The stone here is the same foundation stone described in Isaiah 28:16 and Mark 12:10-11.
The rejection and killing of the son means Israel killing Christ. That work was done by Satan through men gathered under his banner. The rejection brought Christ sorrow not for Himself but for the sins of the people and their lost condition, the same sorrow that made Him weep over Jerusalem.
The husbandmen stand guilty for refusing to return to their lord the fruit of his ground and robbing God of the service He claimed by misleading the people and turning the nation away from Christ. Christ presented the law of God unmixed with human tradition as the great standard of obedience, which aroused their enmity because they had set human teaching above God's word and turned the people away from His precepts. They would not give up man-made commandments to obey the word of God, and would not sacrifice pride of reason and praise of men for the sake of truth. When He presented the claims of God to the nation, the priests and elders denied His right to interpose between them and the people, would not accept His rebukes and warnings, set themselves to turn the people against Him, and to compass His destruction. For the rejection of Christ with the results that followed they are responsible, and a nation's sin and a nation's ruin were due to the religious leaders.
Jesus speaks this as judgment against those rulers: their treatment of God's servants and His Son brings punishment on the Jewish nation. The vineyard will be taken from them, and the kingdom will be given to those who obey its Ruler. The accompanying image in verse 18 warns that those who fall on this stone will be broken, while those on whom it falls will be ground to powder. The parable does not apply alone to the Jewish nation but has a lesson for the church in this generation, which God has endowed with great privileges and blessings and from which He expects corresponding returns. Rejecting the Son of God brings doom: the fate of the unbelieving Jews awaits all who remain impenitent and refuse Him as Redeemer. Safety comes from building on the right foundation, for hopes built on untested foundations will soon collapse and bring down what rests on them.