A credible proclamation of the Gospel requires striving after an "exemplary life," he said. "a life of service that is capable of rejecting all those material things that shrink the heart and make people indifferent and inward-looking; a life that renounces the useless things that entangle the heart in order to find time for God and others."
Francis said: "We can ask ourselves: how am I doing in my efforts to go up? Am I able to reject the heavy and useless baggage of worldliness in order to climb the mountain of the Lord?"
Catholics must think about God and about their brothers and sisters, the pope said, because "this is our mission: to give pure and fresh air to those immersed in the pollution of our world."
Concluding his homily, he urged Catholics to "have courage!" saying "Jesus expects so much from you!"
The Lord wants everyone to know they are his beloved children, he said. "Do you want to quell Jesus' concern? Go and show love to everyone, because your life is a precious mission: it is not a burden to be borne, but a gift to offer. Have courage, and let us fearlessly go forth to all!"
Following Mass, Pope Francis shared a brief message and prayed the Angelus from a window overlooking St. Peter's Square.
In his message, the pope said the day's celebration of World Mission Day is a good time for all the baptized to consider the necessity of their participation in proclaiming the Word of God, and to make a renewed commitment to do so.
"Believers are called to bring everywhere, with new enthusiasm, the good news that, in Jesus, mercy overcomes sin, hope overcomes fear, fraternity overcomes hostility," he said. "Christ is our peace and in Him every division is overcome, in Him alone is there the salvation of every man and every people."
Francis added that to share Christ effectively, however, prayer is "indispensable," and asked Catholics to pray in a special way for the Church's missionaries, including those who go to far places to share God's Word.