The Virgin appears miraculously to Saint Bernard to offer him her milk as a reward for his praises and defense. The Saint is surprised while studying and falls to his knees. His desk and bookshelves appear behind him and other books, and an abbot's staff, lie on the floor.

The subject and size of this work suggest that it was probably an altar painting made for a Cistercian convent. Yet, there is no known documentation until it appeared in the collection of Queen Isabel Farnesio in 1745.

Throughout his career, Murillo alternated paintings of single figures with large works featuring more ambitious compositions. This work includes figures and elements which the artist was fond of painting, including the Virgin with Child, cherubs, the luminous celestial opening of the sky, and the magnificent still-life details, represented here by flowers and books.