וְהָי֣וּ חַיֶּ֔יךָ תְּלֻאִ֥ים לְךָ֖ מִנֶּ֑גֶד וּפָֽחַדְתָּ֙ לַ֣יְלָה וְיוֹמָ֔ם וְלֹ֥א תַאֲמִ֖ין בְּחַיֶּֽיךָ׃
And thy life shall hang in doubt before thee; and thou shalt fear night and day, and shalt have no assurance of thy life.
Read kabbalistic (mystical) interpretation of Deuteronomy 28:66: and classical mystical sources.