The problem is that Supernatural Grace doesn’t seem to conquer concupiscence. One can receive grace and fall from grace. It doesn’t make it easier to avoid sin.
It is ridiculously easy to fall from grace, it is horrendously difficult to stay there due to concupiscence. God’s grace is fragile and very easy to lose.
In other words, the software is still buggy, grace hasn’t fixed the bug.
I don’t think that is the definition of sufficient, that’s the definition of “begrudgingly providing the bare minimum” Scripture says where sin abounds, grace abounds the more. This tells me that grace is supposed to be not just sufficient, but plentiful and one’s cup is overflowing.
That doesn’t seem to fit my experience. Concupiscence is still there and bullying people into submission.
That’s another good way of looking at it.
Catholic Encyclopedia has something to help understand the topic that Adam and Eve were free from concupiscence, but we are not:
The first parents were free from concupiscence, so that their sensuous appetite was perfectly subject to reason; and this freedom they were to transmit to posterity provided they observed the commandment of God. A short but important statement of the Catholic doctrine on this point may be quoted from Peter the Deacon, a Greek, who was sent to Rome to bear witness to the Faith of the East:
“Our belief is that Adam came from the hands of his Creator good and free from the assaults of the flesh” (Lib. de Incarn., c. vi). In our first parents, however, this complete dominion of reason over appetite was no natural perfection or acquirement, but a preternatural gift of God, that is, a gift not due to human nature; nor was it, on the other hand, the essence of their original justice, which consisted in sanctifying grace; it was but a complement added to the latter by the Divine bounty. By the sin of Adam freedom from concupiscence was forfeited not only for himself, but also for all his posterity with the exception of the Blessed Virgin by special privilege. Human nature was deprived of both its preternatural and supernatural gifts and graces, the lower appetite began to lust against the spirit, and evil habits, contracted by personal sins, wrought disorder in the body, obscured the mind, and weakened the power of the will, without, however, destroying its freedom. Hence that lamentable condition of which St. Paul complains when he writes:
I find then a law, that when I have a will to do good, evil is present with me. For I am delighted with the law of God, according to the inward man: but I see another law in my members, fighting against the law of my mind, and captivating me in the law of sin, that is in my members. Unhappy man that I am, who shall deliver me from the body of this death? (Romans 7:21-25)
Also, it is only our by our free will that mortal sin occurs through the temptations of concupiesence.
From the explanation given, it is plain that the opposition between appetite and reason is natural in man, and that, though it be an imperfection, it is not a corruption of human nature. Nor have the inordinate desires (actual concupiscence) or the proneness to them (habitual concupiscence) the nature of sin; for sin, being the free and deliberate transgression of the law of God, can be only in the rational will; though it be true that they are temptations to sin, becoming the stronger and the more frequent the oftener they have been indulged. As thus far considered they are only sinful objects and antecedent causes of sinful transgressions; they contract the malice of sin only when consent is given by the will; not as though their nature were changed, but because they are adopted and completed by the will and so share its malice. Hence the distinction of concupiscence antecedent and concupiscence consequent to the consent of the will; the latter is sinful, the former is not.
Ming, J. (1908). Concupiscence. In The Catholic Encyclopedia. New York: Robert Appleton Company.
newadvent.org/cathen/04208a.htm
A definition of
Sufficient Grace from
Modern Catholic Dictionary may help:
Actual grace considered apart from the supernatural effect for which it was bestowed. It may therefore mean the grace that does not meet with adequate co-operation on the part of the human recipient, and then it is merely sufficient grace. It is enough to enable a person to perform a salutary act, but who freely declines to co-operate. Or it may simply mean the grace that gives one the power to accomplish a salutary action, as distinct from an efficacious grace, which secures that the salutary act is accomplished.