448、⑷淫行是一种强烈的性欲，但不是对奸淫的性欲。淫行之所以是一种强烈的性欲，是因为：
①它从属世人冒出来，而性欲和情欲就在出自属世人的一切事物里面。属世人无非是性欲和情欲的居所和容器，因为从父母遗传来的各种罪恶都居于此处。
②淫荡者将游荡和淫乱的眼光投向其他异性，而不是限于其中一个异性。只要他处在这种状态，淫欲就会驱使他去行他所行的。但当他专注于一位女性，乐意将自己的生命与她的生命联结起来时，性欲就转化为一种贞洁的情感，情欲则转化为一种人性之爱。
448、（4）放荡的性行为是一种情欲有以原因：
1、它来自于人的自然性自我，来自于自然性自我的一切都有动物般的欲望和贪婪在里面；因为自然自我只是动物般的欲望的存在之处，一切从父母继承下来的应受到指责的性质都处于自然自我中。
2、放荡性行为者会有对异性没有区别地，混杂地爱，而不是将其指向异性中的一个；只要他是处于那种状态中，他就是受情欲推动而行为。但当他只爱一个女人时，他的欲望就会变为贞节的情感，他的爱就会变为人性的爱。
448. (iv) Fornication is a lust, but not a lust for adultery.
The reasons why fornication is lust are: (a) it arises from the natural man, and everything which arises from that is desire and lust. For the natural man is nothing but a container and home for desires and lusts, since all kinds of guilt inherited from parents live there. (b) A fornicator casts a roving and promiscuous eye on the other sex, not yet limiting himself to one of that sex. So long as he is in that state, lust drives him to do what he does. But when he looks to only one woman, and loves to join his life with hers, desire turns into a chaste affection and lust into a civilised love.
448. 4. Fornication is lust, but not the lust of adultery. Fornication is lust for the following reasons:
1. It springs from the natural self, and everything that springs from the natural self has in it animal desire and lust; for the natural self is nothing but an abode and receptacle of animal desires and lusts, inasmuch as all blameworthy characteristics inherited from parents are seated there.
2. A fornicator casts his gaze upon the opposite sex indiscriminately and promiscuously, and does not direct it as yet to one of the sex; and as long as he is in that state, it is lust that moves him to do what he does. But according as he turns his eyes to one, and loves uniting his life with hers, his desire turns into chaste affection, and his lust into human love.
448. 4. Fornication is a desire, but not a desire for adultery. The reasons why fornication is a desire are: (a) It comes from the worldly side of a person, and there is selfishness and lust in everything that comes from that, for the worldly side of a person is nothing but a home and a container of self - interests and passions, since everything blameworthy inherited from your parents settles there.
(b) A fornicator has a roving and promiscuous eye for the other sex and is not looking for one person of the other sex yet, and so long as he is in that condition, passion prompts him to do what he does. But as he inclines toward one and loves to join his life together with her life, lust becomes a chaste affection, and passion becomes human love.
448. IV. THAT FORNICATION IS A LUST, BUT NOT THE LUST OF ADULTERY. The reasons why fornication is a lust are: I. Because it comes forth from the natural man, and in everything coming from the natural man is concupiscence and lust. The natural man is nothing but an abode and receptacle of concupiscences and lusts, for, resident there, is all the guilt inherited from his parents. 2. Because the fornicator looks at the sex roamingly and promiscuously, not as yet looking to one of the sex. So long as he is in that state, it is lust that excites him to do what he does; but as he looks to one, and loves to conjoin his life with her life, concupiscence becomes chaste affection, and lust, human love.
448. (iv) Fornication is lust, but not the lust of adultery. Fornication is lust for the following reasons. 1. It comes from the natural man, and in all which comes therefrom there are concupiscence and lust. For the natural man is nothing but an abode and receptacle of concupiscences and lusts, since all guilt inherited from parents resides there. 2. A fornicator looks rovingly and promiscuously upon the sex, and not yet to one of the sex; as long as he is in that state, lust excites him to do what he does; but as he looks to one woman, and loves to unite his life with hers, concupiscence becomes chaste affection, and lust becomes human love.
448. (4) That fornication is lust, but not the lust of adultery. That fornication is lust is from these causes; (1) That it comes from the natural man, and in all that comes from that man there is concupiscence and lust; for the natural man is nothing but an abode and receptacle of concupiscences and lusts, since all the propensities to evil inherited from parents reside there. (2) Because the fornicator looks vagrantly and promiscuously towards the sex, and not yet to one of the sex, and so long as he is in that state lust incites him to the doing of what he does; but in proportion as he looks to one, and loves to conjoin his life with her life, concupiscence becomes chaste affection, and lust becomes human love.
448. IV. Quod fornicatio sit libido, sed non libido adulterii. Quod fornicatio sit libido, sunt causae. 1. Quia prodit ex naturali homine, et in omni, quod ex illo prodit, est concupiscentia et libido, naturalis enim homo non est nisi quam concupiscentiarum et libidinum domicilium et receptaculum, omnes enim reatus a parentibus haereditati ibi resident. 2. Quia fornicator spectat vage et promiscue ad sexum, et nondum ad unam e sexu, et quamdiu in illo statu est, excitat illum libido ad agendum quod agit; sed sicut spectat ad unam, ac amat vitam suam conjungere cum ejus vita, concupiscentia fit affectio casta, ac libido fit amor humanus.