Saint Montfort's spirituality is a way for montfortians to get closer to Jesus Christ and live their vocation. But not only the Montfortian who live it, many lay people also draw enthusiasm and spirituality.

Montfort died, but his followers such as Fr. Adrien Vetel, Fr. René Mulot, and Br. Mathurin continued the work and spirituality of Montfort for generations to come. What exactly is Saint Montfort's spirituality? Montfort or Montfortian Spirituality is the Spirituality of the Cross and Marian. Simply seen in the logo: DS, AM (DS=Deo Soli, AM=Ave Maria). Deo Soli (Only Allah) shows the totality of the Montfortian to surrender themselves to God like the total surrender (emptying) of Christ's self to humans in the events of the Incarnation and the Cross. Ave Maria (AM) reveals the Marian dimension in the way the Montfortian live their surrender to God. Maria became a model for Deo Soli. One cannot surrender totally to God (Deo Soli) without Marian's values living in his heart. Then Saint Montfort's spirituality is Spirituality SELF-DELIMINATION to Jesus through Mary. Montfort departs from his thesis “through Mary Jesus came into the world and through Mary also He must reign in the world” (BS 1). To reign in the world means to become more united and like humans to Christ. That unity and likeness only occur in and through Mary. Because, if Jesus took the human form in the womb of Mary (kenosis in the incarnation), then in turn the same womb becomes the place of formation of human beings to become divine (theosis in devotion). Kenosis is a “down” process whereas theosis is an “up” process. Both the "down" process and the "up" process, Mary remains a mall for the transfiguration process: becoming human from God's side and divine from the human side. This is why Montfort said “if the head of mankind, Jesus Christ was born of Mary, then naturally the elect who were members of that head, was born of this woman. It is impossible for the same mother to give birth to a head without members, nor can it be possible for members without a head (TD 32)”. This is God's will, because Montfort said, “God the Father wants until the end of time to create His children through Mary” (TD 34). Actually here Montfort is talking about Mary's spiritual motherhood role, namely that Mary is personally and completely involved in her motherhood, cooperating with the Three Divine Persons in order to regenerate us into the likeness of Christ.

For Montfort, self-dedication to Jesus through Mary is the perfect form of renewing the baptismal vows. Montfort's logic was simple, almost all Christians betrayed the loyalty they had promised to Jesus at baptism. Where would this confusion come from – says Montfort – if not for people forgetting to live up to the promises and commitments of holy baptism (TD 127-130). So, for Montfort, just as the Council of Trent and the Church Fathers said that the best way to treat this disease of forgetfulness is to renew the baptismal vows. For "we carry this treasure (the grace poured out in baptism), which is more valuable than heaven and earth in a fragile vessel" (TD 87). And for complete renewal of the baptismal vows, only can take place in SELF-DEDICATION to Jesus through Mary. Because, we do this service personally, voluntarily, and consciously than when we are baptized, sometimes the promise is conveyed through the mouths of other people (parents, godparents, etc.). In terms of formula, there are four formulas of SELF-RESERVATION written by Montfort, and one of the formulas is used in Legion Maria's promise. The question is, why is the renewal now "through Mary". Let the answer be clear, it is because Mary is a person who has achieved her goal precisely because she faithfully lives her basic calling. So, he will teach the faithful how to reiterate and live the YES that was said at baptism. Here the renewal of the baptismal vows is the same as the renewed commitment to being anew in Christ. To be anew in Christ, Mary becomes a kind of filter that filters every act of our life of faith. The more Marian a person becomes, the more like he is to Jesus Christ and this is the true meaning of our baptism: to be wholly Jesus' (Totus Tuus – says Montfort).

Saint John Paul II was so convinced of Montfort’s spirituality that the pope in his Encyclical "Redemptoris Mater" wrote "among the many witnesses and teachers of the Spirituality of Mary, we recall the figure of Saint Louis-Marie Grignion de Montfort who proposed self-dedication to Christ through the hands of Mary as an effective means for Christians to faithfully live their baptismal promises (SM. 48). And again the pope whose motto Totus Tuus is taken from the writings of Montfort. He said that " Grignion de Montfort leads us into the heart-mystery which, above our faith, grows and bears fruit” – and which lives are the mystery of baptism.