Six times in Matthew
5 (v21, 27, 31, 33, 38 and 43), the Lord Jesus refers to things his audience had heard said. Some of these things are the direct commands of God through Moses in
something very close to their original wording. Others appear to be
rabbinical interpretations that expand on the originals.
In all cases, the conventional rabbinical readings are inadequate. So instead, the Lord infers from the Law of Moses principles of conduct and modes of thought by which his listeners might strive to exceed the righteousness of
the scribes and Pharisees.
Hearsay, it appears, was
not good enough.