Be the Kingdom of God or You're a Waste
Matthew 7:6 has often baffled commentators. Understood as a chiasmus this verse fits into the Sermon very well. It is an exhortation to be kingdom-people, governed by the law of Christ...or else...you will not be the valuable possession God has called you to be. You will be without value, like pearls to swine. You will be without separated-purpose, like sacrificial-meat given to dogs. On the other hand we will be like salt thats salty, and like light that illuminates; we will have special value, and be of a special purpose, IF we act on the Gospel teaching of our Lord, Jesus.
The excerpt below on the topic of chiasmus was taken from the "in the beginning" website.
In general, chiasmus refers to an inverted parallelism or sequence of words or ideas in a phrase or clause, sentence, paragraph, chapter, or an entire literary work. For example, Matthew 7:6 contains a simple chiasmus which may be represented as follows:
A "Do not give what is holy to dogs,
B and do not throw your pearls before swine,
B’ lest they trample them under their feet,
A’ and turn and tear you to pieces"
In this instance, the propositions A and B are reflected as in a reversed mirror image by the propositions B’ (said as "B prime") and A’ (said as "A prime"). By recognizing Matthew 7:6 as a chiastic structure, one can make much better sense of this verse than might otherwise be done; for it seems most logical that the dogs (A) tear to pieces (A’), and the swine (B) do the trampling (B’).