וְשַׂמְתִּ֣י פְדֻ֔ת בֵּ֥ין עַמִּ֖י וּבֵ֣ין עַמֶּ֑ךָ לְמָחָ֥ר יִהְיֶ֖ה הָאֹ֥ת הַזֶּֽה׃
And I will put a division between My people and thy people—by to-morrow shall this sign be.’
Read halakhic rulings (Jewish law) on Exodus 8:19: and classical halakhic sources.