Section — Slater, Manual of Moral Theology
Section II. The Purpose of Amendment
We saw in the preceding section that contrition is essentially a turning away with hatred from sin in order to approach to God, and so all true contrition necessarily implies a purpose not to sin again. If the truly contrite sinner thinks of the future, he can scarcely fail to form an explicit purpose of amendment, and some theologians hold that this explicit purpose is necessary, otherwise why should it find a place in the definition of contrition given by the Council of Trent? On account of its importance, it is well that the purpose of amendment should always be explicit, but still as it is virtually contained in all true sorrow for sin, and the fact that the Council explicitly mentions it does not prove that it must necessarily be explicit, the opinion which denies the absolute necessity of an explicit purpose of amendment for the validity of Penance is safe. A Roman council held in 1725 under Benedict XIII issued an instruction explaining how to make one’s confession, and it only insists on an implicit purpose of amendment.
p. ii, 136
Whether it be explicit or implicit, the purpose of amendment must be sincere, efficacious, and universal.
It must be sincere, with a genuine intention to avoid sin in the future; it will not suffice to make profession of good intentions with the lips, without any real determination to carry them into effect.
It must be efficacious, or the sinner must be prepared to take the necessary means to avoid sin. A mere half wish and half resolve will not do. The sinner must be prepared to do and suffer anything rather than fall into sin again. It would, indeed, be unwise to try one’s own determination by imagining all kinds of terrible temptations to sin to see if the will would remain constant, but at any rate the will must here and now be so rooted in good that, come what may, it is determined not to be moved.
There must also be a firm resolve to avoid all mortal sins for the future, not merely any that may have been confessed, but all others, or else there can be no friendship with God, whom we must love above all things. He cannot love God above all things who is prepared to offend him mortally. The purpose of amendment need not extend to all venial sins, provided that at least there is the sincere intention of avoiding some sin that is confessed, or at any rate of lessening the number of smaller transgressions,
p. ii, 136–137