Matthew 5:19 illustrates several aspects of Greek. Perhaps the most interesting is how Greek can drop words out of the second half of a sentence that is parallel in structure. But it also shows the different meanings of οὕτως, and how a long clause can be the subject of the verb and also have it repeated with a demonstrative pronoun. I still remember in second grade a poster of a man with two hats, and the caption said, "The man he." That's poor English, but acceptable Greek, perhaps good Greek.