"In this way, we have come to the second fundamental thought of today's readings. It speaks above all of the goodness of God's creation and of the greatness of the election with which he seeks and loves us. But it also speaks about the history that occurred later, man's failure.
"God had planted choice vines and yet they yielded wild grapes. What are the wild grapes? The good grapes that God expected, says the prophet, would have consisted in justice and uprightness. Wild grapes on the contrary are violence, the shedding of blood and oppression, which make people groan under the yoke of injustice.
"In the Gospel, the image changes: The vineyard produces good grapes, but the tenant winegrowers keep them. They are not willing to give them to the proprietor. They beat and kill his messengers and kill his son. Their motivation is simple: They want to become proprietors; they take what does not belong to them.
"In the Old Testament, what appears first of all is the accusation of the violation of social justice, contempt for man by man. Deep down, however, one sees that with contempt for the Torah, for the law given by God, there is contempt for God himself; there is only a desire to enjoy power itself. This aspect is fully underlined in Jesus' parable: The tenants do not want to have a master and these tenants serve as a mirror for us, men, who usurp the creation which has been entrusted to us to manage.
"We want to be the sole owners in the first person. We want to possess the world and our own life in an unlimited manner. God annoys us or we make of him a simple devout phrase or deny him altogether, eradicating him from public life, so that in this way he no longer has any meaning at all. Tolerance that only admits God as a private opinion, but that denies him the public domain, the reality of the world and of our life, is not tolerance but hypocrisy.
"Whenever man becomes the only owner of the world and proprietor of himself there can be no justice. Only the expedient of power and interests con dominate there. It is true, the son can be expelled from the vineyard and killed to enjoy selfishly the fruits of the earth. But then the vineyard soon becomes an uncultivated plot, trampled on by wild boars, as the responsorial psalm says (cf. Psalm 79:14)."
--Pope Benedict XVI, from the Homily for the opening of the Synod