Certainly, Our Lady has asked us to pray the Rosary at Fatima and Lourdes. But note that she ASKED us; she didn’t COMMAND us. The Church existed several centuries before the Rosary came about. While it is the most indulgenced of all devotions, it is not the only devotion that the Church has. They are all pleasing to God, such as the Divine Mercy chaplet, the Stations of the Cross, the Brown Scapular and so forth. They are devotions and therefore, they help us to live out our baptismal promises. But they are not, in themselves, essential for salvation. We know of them through private revelations. Only what we know by public revelation is essential for salvation. Public revelation ended with the death of the last Apostle.
Fr. Vincent Serpa, O.P.