“You have heard that it was said to the ancient ones, ‘You shall not murder;’and ‘Whoever murders will be in danger of the judgment.’ But I tell you that everyone who is angry with his brother without a cause [a] will be in danger of the judgment. Whoever says to his brother, ‘Raca!’ will be in danger of the council. Whoever says, ‘You fool!’ will be in danger of the fire of Gehenna. (Matthew 5:21-22)
In rabbinic tradition, it is common for a sage to cite a passage from the Torah or a widely accepted interpretation, and then proceed to offer additional insight or even challenge the current understanding. The Talmud is filled with such discussions, where a rabbi says, "It is written…" or "It has been taught…" followed by their own interpretation or commentary. This was not seen as undermining the earlier teaching but was a form of midrash (exposition) designed to deepen the application of the Torah's principles.
Yeshua’s phrasing in Matthew 5: "You have heard it said..." closely resembles this rabbinic method. By quoting a known commandment or tradition and then adding, "But I say to you," Yeshua is participating in the Jewish tradition of interpreting the Torah, which is intended to bring out the full meaning of the text.