אַֽל־תַּעֲל֔וּ כִּ֛י אֵ֥ין יְהוָ֖ה בְּקִרְבְּכֶ֑ם וְלֹא֙ תִּנָּ֣גְפ֔וּ לִפְנֵ֖י אֹיְבֵיכֶֽם׃
Go not up, for the LORD is not among you; that ye be not smitten down before your enemies.
Read kabbalistic (mystical) interpretation of Numbers 14:42: and classical mystical sources.