 When brethren dwell together, it's the same word that James used, my brethren counted all joy. He's not just talking to men. He's talking about a select group of people of like mind. In other words, now he says, notice what happens when they live together. They are dwelling together. It is coming out of this concept of Deuteronomy where community was not defined so much by bloodline, but it was defined by community.