Garrigou-Lagrange helps us understand a basic principle that sanctifying grace is not extrinsic to us but intrinsic. It is a permanent condition of the soul, which some of the synod fathers do not understand.
When one loses sanctifying grace, which is participation in the Divine, one cannot "make grace" or "make virtue" happen. God's gift of grace remains necessary.
A key paragraph from Reality helps us see the layers of meaning presented by this genius, Garrigou-Lagrange.
Sanctifying grace, then, is a participation, not, like actual grace, virtual and transient, but formal and permanent. Still this participation is, not univocal, but analogical, because the divine nature is independent and infinite, whereas grace is essentially finite and dependent on God. Further, grace is an accident, not a substance, and the utmost knowledge it can give us of God is only intuitive, never absolutely comprehensive. Nevertheless this participation, though it is analogical, is still a participation in the deity as deity, since it is the source of the light of glory which enables us to see God as He is in Himself, the deity as deity. Now the deity as deity, though it pre-contains formally all perfections, being, life, intelligence, which it can communicate to creatures, still transcends infinitely all these perfections.  The stone, by participating in being, has an analogical resemblance to God as being. The plant, participating in life, has an analogical resemblance to God as living. Our soul, participating in intelligence, has an analogical resemblance to God as intelligent. But sanctifying grace alone is a participation in the deity as deity, a participation which is naturally impossible and hence naturally unknowable. Only the obscure light of infused faith here below, and only the light of of glory there above, can let us see the deity as deity, God as He is in Himself.
We are here in a world of truth far beyond the reach of reason. Hence, first, the adversaries of the faith can never prove that sanctifying grace is impossible. But, secondly, neither can its possibility be rigorously demonstrated by reason. What, then, of the arguments we have just been proposing? They are arguments of appropriateness, profound indeed and inexhaustible, but since they move in an order beyond reason and philosophy, they can never be apodictically demonstrative. Both the intrinsic possibility of grace and its existence are affirmed with certitude, not by reason, but by faith alone. .
In baptism. we are not merely adopted, but taken into God's Own Life. This participation is intrinsic to the soul, within, not without, as the Lutherans and some other Protestants believe.
I have posted these thoughts before under "grace", but I want to be more pointed in my examination of the lack of understanding of grace among some bishops and cardinals. They seem not to understand Christ, the Second Person of the Blessed Trinity. Garrigou-Lagrange clarifies this Scriptural based definition of the ability to turn against grace.
First, and again, a look at the different kinds of grace.
Efficacious grace, in contrast with sufficient grace which can remain sterile, is infallibly followed by a meritorious act. This efficacious grace, so Thomists maintain, is intrinsically efficacious because God wills it; not merely extrinsically efficacious, that is, by the consent of our will.
We shall consider first the texts of St. Thomas which express this doctrine, then the Scriptural texts on which it reposes. The main distinction here is that between God's antecedent will and God's consequent will, a distinction fully in harmony with that between potency and act.
Commenting on St. Paul,  St. Thomas writes: "Christ is the propitiation for our sins, for some efficaciously, for all sufficiently, because the price, which is His blood, is sufficient for universal salvation, but, by reason of impediment, is efficacious only in the elect." God removes this impediment, but not always. There lies the mystery. God, he says again,  withholds from no one his due. Again:  the New Law gives of itself sufficient aid to shun sin. Then, commenting on the Ephesians,  he becomes more precise: God's aid is twofold. One is the faculty of doing, the other is the act itself. God gives the faculty by infusing power and grace to make man able and apt for the act. God gives further the act by inner movement to good, working in us both to will and to do. .
In other words, God is active in our participation in this grace. God makes us able to accept His grace, and leads the person in grace to a particular action, which is, therefore, good and a gift. Again, the idea that men and women do not have grace to pursue holiness is sheer heresy.
All men receive concurrence of grace which makes them able to fulfill the divine precepts, because God never commands the impossible. As regards efficacious grace, by which a man actually observes God's commands, if it is given to one, it is given by mercy, if it is refused to another, it is refused by justice.  If man resists the grace which makes him able to do good, he merits deprival of that grace which gives him the actual doing of good. By His own judgment, says St. Thomas,  God does not give the light of grace to those in whom he finds an obstacle.
We choose to live against God's Will for us, a life in grace.
This resistance of grace is entirely in our own wills. Because sanctifying grace is a permanent quality of life, one begins to think and act like God. One begins to rest in His Will. If one is not in sanctifying grace, without actual grace, or prevenient grace, one cannot come into this mode of being which is thinking and acting like God.
Many people in the Catholic Church are denying natural law. The reason for this is that natural law has been separated from sanctifying grace. Grace informs nature, sanctifies and makes holy what is natural to man. So, a natural virtue of prudence becomes "supernaturalized" by grace.
Natural law becomes clouded in both the will and the intellect by the lack of grace. Many of us have noted how many people are no longer baptized. Some low-church Protestant denominations do not believe in child-baptism and merely "consecrate" their babies to God.
Sorry, but consecration does not involve grace. The children grow up without the intellect, will, body, imagination, etc. being informed by infused knowledge and the theological virtues. One reason for the fast decaying of our Christian cultures must be this willing ignorance of grace as directly coming from baptism. One reason for the devolution of human intelligence, and teachers who are honest have noticed this, is that children are not allowed the grace which informs the intellect. Without grace, natural law can be set aside by those who choose not to be fully human. To be fully human, because we are made in the image and likeness of God, demands a participation in grace.
Garrigou-Lagrange writes something startling. Even the demons have acquired faith, that is faith based on their experience of miracles. Faith in God in the demons is not infused faith, as in the person who has been baptized.
Here is G-L again on the basic grace of conversion:
Sufficient grace is not sterile, it produces a good thought, a good movement of will, some disposition to consent. It is called sufficient, says Alvarez,  as counter-distinguished from "simply efficacious." But each sufficient grace is in a sense efficacious, i. e.: in its own order.
But each meritorious act, however small, requires a grace simply efficacious. It is good here and now realized, hence presupposes an eternal decree of God's consequent will. Nothing comes to pass hic et nunc, unless God has efficaciously willed it (if it is good) or permitted it (if it is evil).  We cannot, says Bossuet,  refuse to God the power of actualizing our free and salutary choice, without which no merit can exist.
3. Resistance to sufficient grace is an evil, arising from us, from our defectibility and our actual deficience, whereas our non-resistance is, on the contrary, a good, arising from ourselves as second causes, but from God as first cause.
What some of the synod fathers forget, or refuse to admit, is that resistance to sufficient grace, a great evil, comes from our own imperfections, which is why we must all pray daily for this grace of perfection. That a priest told me we can move beyond venial sin, and that insight from prayer that concupiscence can be destroyed, (http://supertradmum-etheldredasplace.blogspot.com/2015/04/to-destroy-concupiscence.html), both are truths which emphasize the call to holiness through grace.
I am moving towards a more in-depth discussion on the Indwelling of the Trinity, but one can follow the tags to previous posts until I get to these posts.
In the meantime, I hope readers are beginning to see the great dangers of those who are denying the very doctrines of grace and free will held to sacred in our Church.