Obj. 4:  Further, the external act of fornication or adultery is a mortal sin, not by reason of the delectation, since this is found also in the marriage act, but by reason of an inordinateness in the act itself.  Now he that consents to the delectation does not, for this reason, consent to the inordinateness of the act.  Therefore he seems not to sin mortally.

Obj. 5:  Further, the sin of murder is more grievous than simple fornication.  Now it is not a mortal sin to consent to the delectation resulting from the thought of murder.  Much less therefore is it a mortal sin to consent to the delectation resulting from the thought of fornication.

Obj. 6:  Further, the Lord’s prayer is recited every day for the remission of venial sins, as Augustine asserts (Enchiridion lxxviii).  Now Augustine teaches that consent to delectation may be driven away by means of the Lord’s Prayer:  for he says (De Trin. xii, 12) that “this sin is much less grievous than if it be decided to fulfil it by deed:  wherefore we ought to ask pardon for such thoughts also, and we should strike our breasts and say:  ‘Forgive us our trespasses.’” Therefore consent to delectation is a venial sin.

On the contrary, Augustine adds after a few words:  “Man will be altogether lost unless, through the grace of the Mediator, he be forgiven those things which are deemed mere sins of thought, since without the will to do them, he desires nevertheless to enjoy them.”  But no man is lost except through mortal sin.  Therefore consent to delectation is a mortal sin.

I answer that, There have been various opinions on this point, for some have held that consent to delectation is not a mortal sin, but only a venial sin, while others have held it to be a mortal sin, and this opinion is more common and more probable.  For we must take note that since every delectation results from some action, as stated in Ethic. x, 4, and again, that since every delectation may be compared to two things, viz. to the operation from which it results, and to the object in which a person takes delight.  Now it happens that an action, just as a thing, is an object of delectation, because the action itself can be considered as a good and an end, in which the person who delights in it, rests.  Sometimes the action itself, which results in delectation, is the object of delectation, in so far as the appetitive power, to which it belongs to take delight in anything, is brought to bear on the action itself as a good:  for instance, when a man thinks and delights in his thought, in so far as his thought pleases him; while at other times the delight consequent to an action, e.g. a thought, has for its object another action, as being the object of his thought; and then his thought proceeds from the inclination of the appetite, not indeed to the thought, but to the action thought of.  Accordingly a man who is thinking of fornication, may delight