«DIVINUM ILLUD». - Encyclical of Leo XIII, 9 May 1897 (Acta Leonis XIII, 17 [1898], pp. 125–48) on the Holy Spirit, His sanctifying work in the Church and in souls, and the consequent duty to remember Him, invoke Him, and heed His inspirations.
After some reflections on devotion to the Most Holy Trinity, which should not be lacking in the life of every Christian, the encyclical systematically treats of the particular mission of the Holy Spirit. This mission, once exercised for the glorification of Jesus during His earthly life, continues and will continue until the end of the world for the benefit of the Church, which He founded. He is, in fact, the guarantee of the supreme ecclesiastical magisterium, to which He ensures infallibility; He watches over the growth of the “pusillus grex,” which must embrace all peoples; He lavishly diffuses His charisms and gifts of light, strength, and love in souls, in which He dwells by grace, producing that splendid flowering of heroic souls and saints who form the fairest adornment of the Church.