To him which divided
gazar  (gaw-zar')
to cut down or off; (figuratively) to destroy, divide, exclude, or decide -- cut down (off), decree, divide, snatch.
the Red
cuwph  (soof)
a reed, especially the papyrus -- flag, Red (sea), weed.
yam  (yawm)
from an unused root meaning to roar -- sea (-faring man, (-shore), south, west (-ern, side, -ward).
into parts
gezer  (gheh'-zer)
something cut off; a portion -- part, piece.
for his mercy
checed  (kheh'-sed)
kindness; by implication (towards God) piety: rarely (by opposition) reproof, or (subject.) beauty
endureth for ever
`owlam  (o-lawm')
concealed, i.e. the vanishing point; generally, time out of mind (past or future), i.e. (practically) eternity; frequentatively, adverbial (especially with prepositional prefix) always