"May Mary Most Holy help us feel every day the joy and amazement of being called by God to work for him, in his field which is the world, in his vineyard which is the Church. And to have his love, the friendship of Jesus, as the only reward," he prayed.
The pope said another lesson the parable teaches is the master's attitude toward the call.
The landowner goes out five times to the square to call people to work for him. This image of an owner going out to look for workers for his vineyard "is touching," he noted.
He explained that the "master represents God who calls everyone and always calls, at any time. God acts like this today too: he continues to call anyone, at any time, to invite them to work in his Kingdom."
And Catholics are called to accept and imitate this, he emphasized. God is constantly searching for us "because he wants no one to be excluded from his design of love."
This is what the Church must do, he said, "always going out; and when the Church is not going out, she falls ill with so many evils that we have in the Church."
"And why these diseases in the Church? Because it is not going out. It is true that when one goes out there is the danger of an accident. But it is better a damaged Church going out, to proclaim the Gospel, than a Church sick from closure," he added.
"God always goes out, because he is Father, because he loves. The Church must do the same: always going out."
Hannah Brockhaus is Catholic News Agency's senior Rome correspondent. She grew up in Omaha, Nebraska, and has a degree in English from Truman State University in Missouri.