כִּֽי־גוֹי֙ עָלָ֣ה עַל־אַרְצִ֔י עָצ֖וּם וְאֵ֣ין מִסְפָּ֑ר שִׁנָּיו֙ שִׁנֵּ֣י אַרְיֵ֔ה וּֽמְתַלְּע֥וֹת לָבִ֖יא לֽוֹ׃
For a people is come up upon my land, Mighty, and without number; His teeth are the teeth of a lion, And he hath the jaw-teeth of a lioness.
Read halakhic rulings (Jewish law) on Joel 1:6: and classical halakhic sources.