What is my strength
koach (ko'-akh)
from an unused root meaning to be firm; vigor, literally (force, in a good or a bad sense) or figuratively (capacity, means, produce); also (from its hardiness) a large lizard
that I should hope
yachal (yaw-chal')
to wait; by implication, to be patient, hope -- (cause to, have, make to) hope, be pained, stay, tarry, trust, wait.
and what is mine end
qets (kates)
an extremity; adverbially (with prepositional prefix) after -- + after, (utmost) border, end, (in-)finite, process.
that I should prolong
'arak (aw-rak')
to be (causative, make) long -- defer, draw out, lengthen, (be, become, make, pro-)long, + (out-, over-)live, tarry (long).
my life
nephesh (neh'-fesh)
a breathing creature, i.e. animal of (abstractly) vitality; used very widely in a literal, accommodated or figurative sense (bodily or mental)