3 The field of Catholic Action is extremely vast. In itself it does not exclude anything, in any manner, direct or indirect, which pertains to the divine mission of the Church. Accordingly one can plainly see how necessary it is for everyone to cooperate in such an important work, not only for the sanctification of his own soul, but also for the extension and increase of the Kingdom of God in individuals, families, and society; each one working according to his energy for the good of his neighbor by the propagation of revealed truth, by the exercise of Christian virtues, by the exercise of the corporal and spiritual works of mercy. Such is the conduct worthy of God to which Saint Paul exhorts us, so as to please Him in all things, bringing forth fruits of all good works, and increasing in the knowledge of God. "May you walk worthily of God and please him in all things, bearing fruit in every good work and growing in the knowledge of God."
Source: Il Fermo Proposito (Vatican.va)