C. F. Keil and Franz Delitzsch on Psalms 135:15-18

Psa 135:15-18

For the good of His proved church He ever proves Himself to be the Living God, whereas idols and idol-worshippers are vain - throughout following Psa 115:4-8, but with some abridgments. Here only the אף used as a particle recalls what is said there of the organ of smell (אף) of the idols that smells not, just as the רוּח which is here (as in Jer 10:14) denied to the idols recalls the הריח denied to them there. It is to be rendered: also there is not a being of breath, i.e., there is no breath at all, not a trace thereof, in their mouth. It is different in 1Sa 21:9, where אין ישׁ (not אין) is meant to be equivalent to the Aramaic אין אית, num (an) est; אין is North-Palestinian, and equivalent to the interrogatory אם (after which the Targum renders אלּוּ אית).