According to St. Alphonsus de Liguori (The Glories of Mary) it was
revealed to Saint Elizabeth that at the request of Our Lady, Our Lord
promised 4 principal graces to those devoted to Her Sorrows:
1. That those who before death invoke the divine Mother in the
name of Her Sorrows will obtain true repentance of all their sins;
2. That He will protect all who have this devotion in their tribulations,
and will protect them especially at the hour of death;
3. That He will impress on their minds the remembrance of His
Passion;
4. That He will place such devout servants in Mother Mary’s hands
to do with them as She wishes and to obtain for them all the
graces She desires.
The above are in addition to the 7 Promises attached to the devotion as revealed to St. Bridget of Sweden for praying the 7 Hail Mary's while meditation on Our Lady's Tears and Sorrows.