Generally speaking English translations cannot be relied upon to represent the
structure of the Greek text.
I took a look at Matt 7:6 and it did seem to have a hint of chiasm but the
last element in the ab/ba structure does not really correspond the the first.
The actions of the third and forth elements are both performed by the pigs
(Meyer, Alford, Hendrikson . . .).
I think if you diagram the sentence you will discover that what we have here
is parallelism not chaism. And the parallelism is the most evident in the
first two prohibitions and weaker in the last two warnings.
-- Clayton Stirling Bartholomew Three Tree Point P.O. Box 255 Seahurst WA 98062