'Separate' in the Bible

He who keeps himself separate for his private purpose goes against all good sense.

A brother offended is harder to win over than a fortified city,And contentions [separating families] are like the bars of a castle.

A wise king sifts out the wicked [from among the good]And drives the [threshing] wheel over them [to separate the chaff from the grain].

Though you grind a foolin a mortar with a pestle along with grain,you will not separate his foolishness from him.