are bound to a rule by the vows of their profession.
Therefore they sin mortally by transgressing the things contained in
their rule.

Obj. 2: Further, the rule is enjoined upon a religious in the same
way as a law. Now he who transgresses a precept of law sins mortally.
Therefore it would seem that a monk sins mortally if he transgresses
the things contained in his rule.

Obj. 3: Further, contempt involves a mortal sin. Now whoever
repeatedly does what he ought not to do seems to sin from contempt.
Therefore it would seem that a religious sins mortally by frequently
transgressing the things contained in his rule.

_On the contrary,_ The religious state is safer than the secular
state; wherefore Gregory at the beginning of his Morals [*Epist.
Missoria, ad Leand. Episc. i] compares the secular life to the stormy
sea, and the religious life to the calm port. But if every
transgression of the things contained in his rule were to involve a
religious in mortal sin, the religious life would be fraught with
danger of account of its multitude of observances. Therefore not
every transgression of the things contained in the rule is a mortal
sin.

_I answer that,_ As stated above (A. 1, ad 1, 2), a thing is
contained in the rule in two ways. First, as the end of the rule, for
instance things that pertain to the acts of the virtues; and the
transgression of these, as regards those which come under a common
precept, involves a mortal sin; but as regards those which are not
included in the common obligation of a precept, the transgression
thereof does not involve a mortal sin, except by reason of contempt,
because, as stated above (A. 2), a religious is not bound to be
perfect, but to tend to perfection, to which the contempt of
perfection is opposed.

Secondly, a thing is contained in the rule through pertaining to the
outward practice, such as all external observances, to some of which
a religious is bound by the vow of his profession. Now the vow of
profession regards chiefly the three things aforesaid, namely
poverty, continence, and obedience, while all others are directed to
these. Consequently the transgression of these three involves a
mortal sin, while the transgression of the others does not involve a
mortal sin, except either by reason of contempt of the rule (since
this is directly contrary to the profession whereby a man vows to
live according to the rule), or by reason of a precept, whether given
orally by a sup