Pope Francis on Saturday addressed rail workers, remembering the hard and sometimes deadly work that built the railways of Italy. He invited them all to embrace God’s “medicine of mercy” in the Catholic Church’s year of Mercy.

Speaking to about 7,000 rail workers in Vatican City’s Paul VI Hall, the Pope remembered “the many people who have worked hard” to build the Italian State Railway rail network in its 110 years of existence.   “Not a few workers have also lost their lives in this labor,” he said Dec. 19. “We remember them all — and let us make it so that — so far as it is in our power — such things do not happen anymore.”

He praised the collaboration between Italian railways, local authorities and non-profit organizations that have created support centers to for people in need. These centers help keep Italy united geographically and as a society by preventing people from being left behind.

He also spoke about the Don Luigi Di Liegro homeless shelter and hostel, where he had celebrated Mass on Friday and opened a special Holy Door there for the Catholic Church’s Jubilee Year of Mercy.

The Pope said the Year of Mercy is a reminder that mercy is “the first and most real medicine for humans.” Mercy is “a medicine which everyone needs urgently.”

While mercy from God is continuous and abundant, we must be able to show mercy to each other “so that everyone can live the fullness of his humanity.”

Those who pass through the Holy Door with love will find “forgiveness and consolation,” Pope Francis said. They will be motivated to give generously and to give of themselves, “for the salvation of their brothers.” He encouraged people to take part in the Year of Mercy to help renew society and make it more just and united during a time that the Pope has characterized as a “piecemeal” World War III.

He encouraged Italy and all countries to become places of solidarity networks and to become “more authentically human” and more able to rejoice in the love of God.