Commentary for Nahum 1:2

The Lord is a jealous and vengeful God—Nahum prophesied concerning Sennacherib’s descendants, and in the time of Manasseh, as we find in Seder Olalm (ch.20).

The Lord is a jealous and vengeful God—from the time He avenged Israel upon their enemies, and now too, He is still vengeful and full of wrath. He is destined to wreak vengeance upon His adversaries who destroyed their land and exiled His people. and he bears a grudge Heb. וְנוֹטֵר, lit. watches. He lays up His hatred for His enemies. Rabbi Simon says: These three expressions of vengeance correspond to the three exiles to which Sennacherib exiled Israel, as we find in Seder Olam (ch. 23).