Fr. Mermier had a personal devotion to Mary, Mother of (Compassion) Sorrows and had an altar dedicated to her in the chapel of La Feuillette. Every day he would visit the altar and pray to the Mother of Compassion. Fr Mermier considered the devotion to Mother of Compassion as one of the integral expressions of salesian spirituality . Fr Mermier recalls the fervor with which St Francis de Sales gives insights into the compassionate Mother in his Treatise on the Love of God as she stood at the foot of the Cross on Calvary, the Mount of Lovers.

For his missionaries who had to experience the sufferings of God in the sufferings of humanity , and who were exhorted by Bishop Rey to make their method of approach to sinners like that of St Francis de Sales: full of compassion for sinners.

Mary, Mother of Compassion was the natural patroness for the Congregation that he had founded. Writing to Fr Jacques Martin, the Superior of the Indian Mission, on 21st November 1842,he wrote;

Hymn to the Mother of Sorrows

• Mother most afflicted

  Standing beneath that tree

  Where Jesus hang rejected

• Mary sweetest Mother

  We love to pity thee

• for the sake of Jesus

  Let us thy children be

• Dear and loving mother

  Entreat that we may be

  Near to thee and thy dear Jesus

  Now and eternally