From True Devotion to Mary by St. Louis De Montfort:
Here is what our Blessed Lady revealed to Blessed Alan de Rupe as recorded in his book, The Dignity of the Rosary, and as told again by Cartagena: "Know, my son, and make it known to all, that lukewarmness or negligence in saying the Hail Mary, or a distaste for it, is a probable and proximate sign of eternal damnation, for by this prayer the whole world was restored."
These are terrible words but at the same time they are consoling. We should find it hard to believe them, were we not assured of their truth by Blessed Alan and by St. Dominic before him, and by so many great men since his time. The experience of many centuries is there to prove it, for it has always been common knowledge that those who bear the sign of reprobation, as all formal heretics, evil-doers, the proud and the worldly, hate and spurn the Hail Mary and the Rosary. True, heretics learn to say the Our Father but they will not countenance the Hail Mary and the Rosary and they would rather carry a snake around with them than a rosary. And there are even Catholics who, sharing the proud tendencies of their father Lucifer, despise the Hail Mary or look upon it with indifference. The Rosary, they say, is a devotion suitable only for ignorant and illiterate people.