This will create a paste that the rub will stick to. Here is a recipe for the rub I use on pork shoulders. After you apply a layer of mustard to the pork shoulder, completely coat the shoulder with a good BBQ rub.
yes, its a thing, a noun is a person place or thing. Shelter is a usually used as a noun: We built a shelter to sleep in during the snowstorm. It is also sometimes a verb: We were told to shelter in place during the fire. The trees sheltered us from the hail.
As in English, however, where the word sanctuary can sometimes refer to a refuge,  there are two instances where the Lord refers to himself metaphorically as the sanctuary (i.e., refuge) of faithful Israelites in distress ( Isa 8:14 ; Ezek 11:16 ).