Here's the secret that every saint followed when spreading the Gospel message.
It’s easy for modern-day missionaries, either clergy or laity, to feel “burnt out” after a few years of evangelizing the Christian faith. Weary and tired, the missionary loses their zeal for God and now only “goes through the motions” of their assignment. In extreme cases this burnout can cause someone to give-up their apostolic mission and return to the secular world, jaded by their experience.
The good news is that this does not need to happen. In fact, the saints provide the key to avoid apostolic burnout.
French Trappist monk Dom Jean-Baptiste Chautard relates this secret of the saints in his popular book The Soul of the Apostolate. Below are a few excerpts from his book that explain what is necessary to prevent a missionary from abandoning their vocation.