Sentence:  The inner life of congregations will prosper so long as like-minded people of similar social and economic level can fraternize <WSD>together</WSD> ; the outer life of congregations - the suitability of the environment to their survival - will be propitious so long as the people in the area are of the same social and economic level as the membership . 
Meaning of the word marked with <WSD> tags:  with cooperation and interchange