FOURTH ARTICLE [I-II, Q. 88, Art. 4]

Whether a Venial Sin Can Become Mortal?

Objection 1: It would seem that a venial sin can become a mortal sin.

For Augustine in explaining the words of John 3:36: "He that

believeth not the Son, shall not see life," says (Tract. xii in

Joan.): "The slightest," i.e. venial, "sins kill if we make little of

them." Now a sin is called mortal through causing the spiritual death

of the soul. Therefore a venial sin can become mortal.

Obj. 2: Further, a movement in the sensuality before the consent of

reason, is a venial sin, but after consent, is a mortal sin, as

stated above (Q. 74, A. 8, ad 2). Therefore a venial sin can become

mortal.

Obj. 3: Further, venial and mortal sin differ as curable and

incurable disease, as stated above (A. 1). But a curable disease may

become incurable. Therefore a venial sin may become mortal.

Obj. 4: Further, a disposition may become a habit. Now venial sin is

a disposition to mortal, as stated (A. 3). Therefore a venial sin can

become mortal.

_I answer that,_ The fact of a venial sin becoming a mortal sin may

be understood in three ways. First, so that the same identical act be

at first a venial, and then a mortal sin. This is impossible: because

a sin, like any moral act, consists chiefly in an act of the will: so

that an act is not one morally, if the will be changed, although the

act be continuous physically. If, however, the will be not changed,

it is not possible for a venial sin to become mortal.

Secondly, this may be taken to mean that a sin generically venial,

becomes mortal. This is possible, in so far as one may fix one's end

in that venial sin, or direct it to some mortal sin as end, as stated

above (A. 2).

Thirdly, this may be understood in the sense of many venial sins

constituting one mortal sin. If this be taken as meaning that many

venial sins added together make one mortal sin, it is false, because

all the venial sins in the world cannot incur a debt of punishment

equal to that of one mortal sin. This is evident as regards the

duration of the punishment, since mortal sin incurs a debt of eternal

punishment, while venial sin incurs a debt of temporal punishment, as

stated above (Q. 87, AA. 3, 5). It is also evident as regards the

pain of loss, because mortal sins deserve to be punished by the

privation of seeing God, to which no other punishment is comparable,

as Chrysostom states (Hom. xxiv in Matth.). It is also evident as

regards the pain of sense, as to the remorse of conscience; although

as to the pain of fire, the punishments may perhaps not be

improportionate to one another.

If, however, this be taken as meaning that many venial sins make one

mortal sin dispositively, it is true, as was shown above (A. 3) with

regard to the two different manners of disposition, whereby venial

sin disposes to mortal sin.

Reply Obj. 1: Augustine is referring to the fact of many venial sins

making one mortal sin dispositively.

Reply Obj. 2: The same movement of the sensuality which preceded the

consent of reason can never become a mortal sin; but the movement of

the reason in consenting is a mortal sin.

Reply Obj. 3: Disease of the body is not an act, but an abiding

disposition; wherefore, while remaining the same disease, it may

undergo change. On the other hand, venial sin is a transient act,

which cannot be taken up again: so that in this respect the

comparison fails.

Reply Obj. 4: A disposition that becomes a habit, is like an

imperfect thing in the same species; thus imperfect science, by being

perfected, becomes a habit. On the other hand, venial sin is a

disposition to something differing generically, even as an accident

which disposes to a substantial form, into which it is never changed.

________________________

Summa Theologica, Part I-II (Pars Prima Secundae) From the Complete American Edition · 第 572 / 746 题