Charles Ellicott Commentary Nahum 1:9

"What do ye devise against Jehovah? he will make a full end; affliction shall not rise up the second time." — Nahum 1:9 (ASV)

Affliction — i.e., Nineveh’s affliction of Israel, the same Hebrew word being used in Nahum 1:7 to denote Israel’s “trouble” or “affliction” proceeding from Nineveh . Nineveh will not afflict Israel a second time.

Applying the whole passage to the destruction of Sennacherib’s host, we necessarily prefer this to the other possible interpretation—namely, that God will not need to send affliction on Nineveh a second time, i.e., this visitation will be so exhaustive that there will be no need to repeat it.

For the judgment on Sennacherib was not God’s final visitation.