This apparition is said to be the answer to the prayer of Sister Mary of St. Peter to whom Our Lord entrusted the foundation of the Holy Face Devotion.
Our Lord conveyed to her the evils of communism and gave us this devotion which is a remedy for our evil days.
Being under holy obedience and amidst great struggles with her bishop she prayed to Our Lady to appear somewhere in the world and so she did. Hence one can see the Holy Face Devotion being the root of all the marvellous apparitions which followed from La Salette to Fatima and Akita. You will find below a PDF download of the message of La Salette.