Internal sin, in Christianity, is the idea that
sin
In religious context, sin is a transgression against divine law or a law of the deities. Each culture has its own interpretation of what it means to commit a sin. While sins are generally considered actions, any thought, word, or act considered ...
may be committed not only by outward deeds but also by the inner activity of the mind, quite apart from any external manifestation.
Thought crimes were as old as
heresy
Heresy is any belief or theory that is strongly at variance with established beliefs or customs, particularly the accepted beliefs or religious law of a religious organization. A heretic is a proponent of heresy.
Heresy in Heresy in Christian ...
, but the
Reformation
The Reformation, also known as the Protestant Reformation or the European Reformation, was a time of major Theology, theological movement in Western Christianity in 16th-century Europe that posed a religious and political challenge to the p ...
's alarms received new emphasis at the
Council of Trent
The Council of Trent (), held between 1545 and 1563 in Trent (or Trento), now in northern Italy, was the 19th ecumenical council of the Catholic Church. Prompted by the Protestant Reformation at the time, it has been described as the "most ...
(Session XIV, chapter. v). The session, while reiterating that all
mortal sin
A mortal sin (), in Christian theology, is a gravely sinful act which can lead to damnation if a person does not repent of the sin before death. It is alternatively called deadly, grave, and serious; the concept of mortal sin is found in both ...
s must be confessed, singled out the unspoken ones that "sometimes more grievously wound the soul and are more dangerous than sins which are openly committed".
Three kinds of internal sin are usually distinguished by
Catholics
The Catholic Church (), also known as the Roman Catholic Church, is the largest Christian church, with 1.27 to 1.41 billion baptized Catholics worldwide as of 2025. It is among the world's oldest and largest international institut ...
:
* ''delectatio morosa'', the pleasure taken in a sinful thought or imagination even without desiring it;
* ''gaudium'', dwelling with complacency on sins already committed;
* ''desiderium'', the desire for what is sinful.
Biblical quotes
*
Matthew 5:28 ''But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart''.
*
Romans 6:12 ''Therefore do not let sin reign in your mortal body so that you obey its evil desires''.
See also
*
Cathar
Catharism ( ; from the , "the pure ones") was a Christian quasi- dualist and pseudo-Gnostic movement which thrived in Southern Europe, particularly in northern Italy and southern France, between the 12th and 14th centuries.
Denounced as a he ...
*
Inquisition
The Inquisition was a Catholic Inquisitorial system#History, judicial procedure where the Ecclesiastical court, ecclesiastical judges could initiate, investigate and try cases in their jurisdiction. Popularly it became the name for various med ...
*
Orthodoxy
Orthodoxy () is adherence to a purported "correct" or otherwise mainstream- or classically-accepted creed, especially in religion.
Orthodoxy within Christianity refers to acceptance of the doctrines defined by various creeds and ecumenical co ...
References
Religious law
Sin in Christianity
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