לָ֣מָּה הָיָ֤ה כְאֵבִי֙ נֶ֔צַח וּמַכָּתִ֖י אֲנוּשָׁ֑ה֙ מֵֽאֲנָה֙ הֵֽרָפֵ֔א הָי֨וֹ תִֽהְיֶ֥ה לִי֙ כְּמ֣וֹ אַכְזָ֔ב מַ֖יִם לֹ֥א נֶאֱמָֽנוּ׃ (ס)
Why is my pain perpetual, And my wound incurable, so that it refuseth to be healed? Wilt Thou indeed be unto me as a deceitful brook, As waters that fail?
Read kabbalistic (mystical) interpretation of Jeremiah 15:18: and classical mystical sources.