Saint Thérèse was declared a Doctor of the Church by Pope St. John Paul II because she had developed a specific spirituality that is recognized as something new and important for the Church. She made a consecration to Divine Mercy which she calls her Offering to Merciful Love, which is really the culmination of her whole spiritual teaching on her “Little Way.”
Saint Thérèse understood that the Heart of Jesus is full of mercy for sinners. Yet sinners often close their hearts to Our Lord’s mercy, and this rejection causes Jesus profound suffering. To console His Heart, St. Thérèse asked the Lord to pour into her heart the mercy rejected by others so that everything she did was done for love of Jesus.