In the 7th chapter the Rebbe explains that the animalistic soul which gives the person life, and so too all animals, birds and fish which are permitted to be eaten, and all thoughts, speech and action which aren't forbidden, just they're not for the sake of G-d rather they're for the pleasure of the body, even though they are necessary for living if they aren't for the sake of G-d, all come from the first level of 'the other side' which isn't good or bad, which is called in Hebrew 'Nogah' which means 'a ray of light'. This level of 'nogah' is a middle level between the holiness and the bad, therefore, sometimes it's included in the good and sometimes in the bad. For example: a person that eats juicy meat and drinks good wine in order to open his mind so he should be able to pray and learn Torah better, so the light of 'nogah' which is in the meat or wine goes up and is included in the holiness. And so if one says a jock in order to be happy and then he can learn Torah better, so the speech which in itself isn't holy is included in holiness.