It is one thing to make an "Act of Consecration" to Jesus through Mary; but it is another thing entirely to live out that consecration. And it must be lived out, otherwise it is not a true "consecration". A consecration implies that we dedicate ourselves totally to the service of God, and so it demands that the whole of our life, and every aspect of it, should be affected by that dedication. St Louis Marie de Montfort recognised that this is a difficult thing to achieve; he said:
It is not enough to give ourselves just once as a slave to Jesus through Mary; nor is it enough to renew that consecration once a month or once a week. That alone would make it just a passing devotion and would not raise the soul to the level of holiness which it is capable of reaching. It is easy to enrol in a confraternity; easy to undertake this devotion, and say every day the few vocal prayers prescribed. The chief difficulty is to enter into its spirit, which requires an interior dependence on Mary, and effectively becoming her slave and the slave of Jesus through her. I have met many people who with admirable zeal have set about practising exteriorly this holy slavery of Jesus and Mary, but I have met only a few who have caught its interior spirit, and fewer still who have persevered in it. (Secret of Mary, 44)
From the quotation above, it can be seen that, in the thinking of St. Louis Marie, the essential thing about "living" total consecration lies in what he calls its "interior practices" - that is, not in external things, however praiseworthy, such as prayers, devotional practices, performing external actions; but rather in the attitudes and dispositions of the mind and heart. In both True Devotion to the Blessed Virgin and The Secret of Mary he summarises this "interior" practice or set of practices, by saying that one who has made a total consecration to Jesus through Mary, should strive to do all that they do "through Mary, with Mary, in Mary and for Mary, so as to be able to do it all "through, with, in and for Jesus". These four words, "through", "with", "in" and "for", require some further explanation.
To do all that we do "through" Mary means that we rely on Mary, rather than on ourselves and our own talents or strength, to do all that we do. It means also that we must be led by the spirit of Mary in making our choices in everyday life, and not by any spirit of ambition, self-aggrandisement, self-seeking, that we may find in ourselves.
To do all that we do "with" Mary means that we should try to let Mary accompany us in all that we do, showing us the way, guiding our actions. Or, as St. Louis Marie says in The Secret of Mary, 45, "we must take her as the accomplished model for all that we have to do."
To do all that we do "for" Mary indicates that we do everything for the honour and glory of Mary, as her true slaves; not that we do not do this for the honour and glory of God himself, but in the assurance that Mary will lead us to God. So we consciously try to see what would most please Mary (and God), and do this.
To do all that we do "in" Mary is a little harder to understand; and so will form the topic of a separate page, "Living in Mary".
It must be noted that all of this is in order to do all things through, with, in and for Jesus: Jesus is, as always for St. Louis Marie, the ultimate end of all "true" devotion.