se the perfect would be
worse off than others.

_On the contrary,_ Augustine says on Ps. 5:7, "Thou wilt destroy,"
etc.: "There are two kinds of lie, that are not grievously sinful yet
are not devoid of sin, when we lie either in joking, or for the sake
of our neighbor's good." But every mortal sin is grievous. Therefore
jocose and officious lies are not mortal sins.

_I answer that,_ A mortal sin is, properly speaking, one that is
contrary to charity whereby the soul lives in union with God, as
stated above (Q. 24, A. 12; Q. 35, A. 3). Now a lie may be contrary
to charity in three ways: first, in itself; secondly, in respect of
the evil intended; thirdly, accidentally.

A lie may be in itself contrary to charity by reason of its false
signification. For if this be about divine things, it is contrary to
the charity of God, whose truth one hides or corrupts by such a lie;
so that a lie of this kind is opposed not only to the virtue of
charity, but also to the virtues of faith and religion: wherefore it
is a most grievous and a mortal sin. If, however, the false
signification be about something the knowledge of which affects a
man's good, for instance if it pertain to the perfection of science
or to moral conduct, a lie of this description inflicts an injury on
one's neighbor, since it causes him to have a false opinion,
wherefore it is contrary to charity, as regards the love of our
neighbor, and consequently is a mortal sin. On the other hand, if the
false opinion engendered by the lie be about some matter the
knowledge of which is of no consequence, then the lie in question
does no harm to one's neighbor; for instance, if a person be deceived
as to some contingent particulars that do not concern him. Wherefore
a lie of this kind, considered in itself, is not a mortal sin.

As regards the end in view, a lie may be contrary to charity, through
being told with the purpose of injuring God, and this is always a
mortal sin, for it is opposed to religion; or in order to injure
one's neighbor, in his person, his possessions or his good name, and
this also is a mortal sin, since it is a mortal sin to injure one's
neighbor, and one sins mortally if one has merely the intention of
committing a mortal sin. But if the end intended be not contrary to
charity, neither will the lie, considered under this aspect, be a
mortal sin, as in the case of a jocose lie, where some little
pleasure is intended, or in an officious lie, where