Let the floods
nahar (naw-hawr')
a stream (including the sea; expec. the Nile, Euphrates, etc.); figuratively, prosperity -- flood, river.
clap
macha' (maw-khaw')
to rub or strike the hands together (in exultation) -- clap.;
their hands
kaph (kaf)
the hollow hand or palm (so of the paw of an animal, of the sole, and even of the bowl of a dish or sling, the handle of a bolt, the leaves of a palm-tree); figuratively, power
let the hills
har (har)
a mountain or range of hills (sometimes used figuratively) -- hill (country), mount(-ain), promotion.
be joyful
ranan (raw-nan')
to creak (or emit a stridulous sound), i.e. to shout (usually for joy)
together
yachad (yakh'-ad)
a unit, i.e. (adverb) unitedly -- alike, at all (once), both, likewise, only, (al-)together, withal.