Charles Ellicott Commentary Zephaniah 1:18

"Neither their silver nor their gold shall be able to deliver them in the day of Jehovah`s wrath; but the whole land shall be devoured by the fire of his jealousy: for he will make an end, yea, a terrible end, of all them that dwell in the land." — Zephaniah 1:18 (ASV)

He will make even a speedy riddance. —Literally, He will bring about a destruction, indeed, a terrible one. Compare Isaiah 10:23, from which passage this wording is probably borrowed.