Does lust have mortal vs. venial distinctions?

[Theosopher]

Based on what I could find about theology online, I came to the conclusion a long time ago that lust is always a mortal sin, no exceptions. However, I recently went to confession and mentioned lust, and the priest said that in order to determine if it was mortal, I have to specify whether it was something like a lustful glance or more serious like porn or masturbation. Is this priest right or is he twisting theology? Only informed answers please - I’ve already seen a wealth of personal opinions on this subject.

 

[Buddyroe]

There are mortal lusts:

John 8:42-44 Jesus said unto them, If God were your Father, ye would love me: for I proceeded forth and came from God; neither came I of myself, but he sent me.
Why do ye not understand my speech? even because ye cannot hear my word.
Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it.

 

[humbleseeker]

personal opinions

I’m afraid that’s all your going to get from anonymous strangers on the internet.

 

[Vico]

Based on what I could find about theology online, I came to the conclusion a long time ago that lust is always a mortal sin, …

Lust is grave matter. Catechism:

1857 For a sin to be mortal , three conditions must together be met: "Mortal sin is sin whose object is grave matter and which is also committed with full knowledge and deliberate consent."131

Catholic Encyclopedia

Impurity has the evil distinction that, whenever there is a direct conscious surrender to any of its phases the guilt incurred is always grievous. This judgment, however, needs modifying when there is question of some impure gratification for which a person is responsible, not immediately, but because he had posited its cause, and to which he has not deliberately consented. The act may then be only venially sinful. For the determination of the amount of its wickedness much will depend upon the apprehended proximate danger of giving way on the part of the agent, as well as upon the known capacity of the thing done to bring about venereal pleasure. This teaching applies to external and internal sins alike …

Delany, J. (1910). Lust. In The Catholic Encyclopedia. New York: Robert Appleton Company. http://www.newadvent.org/cathen/09438a.ht