וְאִם־מָאֵ֥ן אַתָּ֖ה לְשַׁלֵּ֑חַ הִנֵּ֣ה אָנֹכִ֗י נֹגֵ֛ף אֶת־כָּל־גְּבוּלְךָ֖ בַּֽצְפַרְדְּעִֽים׃
And if thou refuse to let them go, behold, I will smite all thy borders with frogs.
Read halakhic rulings (Jewish law) on Exodus 7:27: and classical halakhic sources.