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.
