Pope St. Pius X wrote in the encyclical Ad diem illum: “since Mary carries it over all in holiness and union with Jesus Christ, and has been associated by Jesus Christ in the work of redemption, she merits for us de congruo [from appropriateness], in the language of theologians, what Jesus Christ merits for us de condigno [from justice], and she is the supreme Minister of the distribution of graces.”
St. Pius X affirms thus:
–The existence of merit and its nature – from appropriateness.
–The two foundations of this merit: the personal holiness of Our Lady; and the association of the Holy Virgin with her Divine Son in the work of our salvation.
–The extension of this merit: the Virgin Mary’s merit de congruo has the same extension as the merit de condigno of the Savior.
Theology allows us to clarify this precious teaching
The Virgin, who could merit, has title to the promised reward. Her merit is measured by the greatness of her charity, which has no equal or superior, apart from that of Christ. What is its extent?
Certain limits must be assigned to this merit, because what merit is in principle is that it is not deserved.
*To the principle of the universal merit of men: the Incarnation or the divine maternity. Christ Himself did not merit either one.
*To the principle of the personal merit of the Virgin: her Immaculate Conception, her initial grace, her final perseverance.
But it is not necessary to limit Mary’s merit to the graces granted after the Passion. The salvation of the just of the Old Testament could be granted in view of the merits of Jesus Christ and Mary.
What actions of the Virgin merited salvation? For Jesus Christ, all His actions were meritorious, but certain rewards are attached to actions that resemble them. Thus, Jesus’ Passion merits salvation because God wanted to grant salvation in response to this act.
The same goes for Mary’s compassion: God considers the charity of the Mother of God deployed in her compassion and, in response, grants her the salvation of souls merited de congruo.
The comparison of Mary’s merits to those of Christ and the saints allows further clarity
1) The merits of Mary and the merits of Christ.
In its nature, the merit of Jesus Christ is in strict justice; it is joined to the Son’s mission. That of the Virgin is through fittingness: it depends on the charity spread by God in the Virgin’s soul.
In principle, the merit of Jesus has for its foundations the capital grace that allows Him to communicate His merit to His members, as well as the grace of the hypostatic union that gives to it an infinite value. Mary’s merit has for its foundation the fullness of grace and the divine maternity.
2) Our Lady’s merits and those of the other just.
In its extension, Mary’s merit is universal because all receive the fruit of it. This flows from the divine maternity of Our Lady, which gives her a special solicitude for all who will be the members of Christ. Her consent given at the Annunciation encompassed all this work. The merit of a just man is particular: all men do not receive the fruit of a just man’s merit.
According to the application of the fruits of merit, the Virgin merits not only the graces to be applied to men, but also the graces to be acquired for men – in her compassion. But a just man only merits graces to be applied to men.
Thus, the luminous words of St. Pius X reveals to us the extent of Mary’s compassion and the co-redemption, which have merited our salvation, with Christ and through Him.
To be worthy of merit before God, one must possess divine grace; moreover, one must be able to make free acts and, finally, one must still be on earth, on the way – in via as theology says. Here below, Our Lady had these three conditions: she therefore had the capacity to merit. She merited for herself, like the other just. The question asked here is: did she merit for others?