Cannot be crossed
That cannot be crossed. It is forbidden to violate or transgress it.
("The mountains may rise, the valleys may descend, but to this place you have established for them. You set a boundary that they shall not cross, nor return to cover the land," and likewise: "By law, a circle on the surface of the deep – when the circle of the earth was laid on the waters, a law of boundary that cannot be crossed" – Rashi, Proverbs 8:27)
Translation
Expression (Hebrew)
בַּל יַעֲבֹר, בל יעבור
Definition (Hebrew)
שֶׁאֵין לַעֲבֹר אוֹתוֹ. שֶׁאָסוּר לְוַתֵּר אֵלָיו.
("יַעֲלוּ הָרִים יֵרְדוּ בְקָעוֹת אֶל מְקוֹם זֶה יָסַדְתָּ לָהֶם. גְּבוּל שַׂמְתָּ בַּל יַעֲבֹרוּן בַּל יְשׁוּבוּן לְכַסּוֹת הָאָרֶץ", וְכֵן: "בְּחֻקּוֹ חוּג עַל פָנִי תְּהוֹם- כְּשֶׁרֶקַע חוּג הָאָרֶץ עַל הַמַּיִם, חֹק גְּבוּל בַּל יַעֲבֹר"- רָשִׁ"י מִשְׁלֵי ח כז)