Sentence:  Hence the sanctification of the sexual appetite can be regarded as only a single purpose, for which there is not even a point of resemblance in the parallel with the church and her Head, not as the principle task of Christian family morals (Schenkel), as if marriage were ordained as a safeguard against <WSD>whoremongery</WSD> or carnal excess, when this is but a single object, or rather a coincident result, even though the main matter is this work of sanctification. 
Meaning of the word marked with <WSD> tags:  The act of engaging in illicit sexual relations.