Likewise you have asked what is to be believed the perfection of abstinence; and whether it ought to be judged necessary only for the body, or also for the soul. If this virtue which is named abstinence sanctifies the whole man perfectly, it is necessary not only for the body, but also for the soul; because every man consists of body and soul. But in those who, being subject to various vices, forbid themselves something of the things granted for our use, abstinence indeed it must be understood to be, but carnal and imperfect: whereas that abstinence is to be reckoned spiritual and perfect which makes the abstainer a stranger as much from the enticements of carnal pleasures as from all sins;
whose mind the diseases of evil desires do not corrupt, nor do the dainties sought at the command of a domineering gluttony break the strength of his body. Accordingly, he is truly to be believed abstinent who has been made free from all vices, and who, having cut off bodily pleasures, labors not to glut the concupiscence of his flesh, but to sustain his mortal life by the reception of necessaries. Since indeed whatever is received without which life can go on is expended not for sustaining life, but for fostering the luxury of the flesh.
This virtue, therefore, which is called abstinence not only from delicate foods, but also from all evils, although it is necessary for absolutely all men, yet must be believed to be most especially familiar and conjoined to those who, according to what is recorded as having been done in the Acts of the Apostles (4:32), have one heart and one soul, kindled by the fire of divine charity, and to whom, living under the ordering of one head, all things of all become common: if indeed their life is made one for them, just as their substance is made one; and there be in them no diversity of minds, who have a community of resources: because, in order that there might be and exist a holy conjunction of minds, the community of resources was judged necessary.
But what does it profit those who cast away their possessions yet do not relinquish their own wills, since it is far more excellent to renounce one's own will than one's goods? Even the philosophers of this world could cast away their possessions, and now any heretics whatsoever can do so; yet neither did those men live according to the will of God, since they became lovers of their own will; and these latter, by their zeal for their own will, contradict the Lord's will. It is not, therefore, that thing which commends us to God which the very enemies of God also do; but rather that which none but true Christians, and through this lovers of God, accomplish.
These are they who, having cast away their own wills and goods, subject themselves with their whole heart to their Creator, and suspend their own willing upon His will; and therefore whatever the sense of the flesh suggests to them as to be pursued or done, they despise it, captivated by the delight of righteousness.