“The efficacy of an apostolate almost invariably corresponds to the degree of Eucharistic life acquired by a soul. Indeed, the sure sign of a successful apostolate is when it makes souls thirst for frequent and fruitful participation in the Divine Banquet. And this result will never be obtained except in proportion as the apostle himself really makes Jesus in the Blessed Sacrament the source and center of his life.
Like St. Thomas Aquinas, who practically entered the Tabernacle, so to speak, when he wanted to work out a problem, the apostle also will go and tell all his troubles to the Divine Guest, and his action upon souls will be simply his conversations with the Author of Life put into practice.
Our wonderful Father and Pope, Pius X, the Pope of Frequent Communion, was also the Pope of the interior life. ‘Re-establish all things in Christ’ was the first thing he had to say, above all to active workers. It summarizes the program of an apostle who lives on the Eucharist and who sees that the Church will gain successes only in proportion as souls make progress in the Eucharistic life.
So many enterprises in our time, and yet so often fruitless: why is it that they have not put society back on its feet? Let us admit it once again: they can be counted in far greater numbers than in preceding ages, and yet they have been unable to check the frightful ravages of impiety in the field of family life. Why? Because they are not firmly enough based on the interior life, the Eucharistic life, the liturgical life, full and properly understood.
(From The Soul of the Apostolate by Jean-Baptiste Chautard, O.C.S.O.)