אֵ֣ל קַנּ֤וֹא וְנֹקֵם֙ יְהוָ֔ה נֹקֵ֥ם יְהוָ֖ה וּבַ֣עַל חֵמָ֑ה נֹקֵ֤ם יְהוָה֙ לְצָרָ֔יו וְנוֹטֵ֥ר ה֖וּא לְאֹיְבָֽיו׃
The LORD is a jealous and avenging God, The LORD avengeth and is full of wrath; The LORD taketh vengeance on His adversaries, And He reserveth wrath for His enemies.
Read kabbalistic (mystical) interpretation of Nahum 1:2: and classical mystical sources.