This is a generalization that means people from every tribe in Israel came to David, but not every individual. Alternate translation: "people from throughout Israel came to David" or "people from every tribe in Israel came to David" (See: [[rc://en/ta/man/jit/figs-hyperbole]])
This idiom means that they are relatives. Alternate translation: "we are your relatives" or "we have the same ancestors as you" (See: [[rc://en/ta/man/jit/figs-idiom]])