They were a wall
chowmah (kho-maw')
a wall of protection -- wall, walled.
unto us both by night
layil (lah'-yil)
a twist (away of the light), i.e. night; figuratively, adversity -- (mid-)night (season).
and day
yowmam (yo-mawm')
daily -- daily, (by, in the) day(-time).
all the while
yowm (yome)
a day (as the warm hours),
we were with them keeping
ra`ah (raw-aw')
to tend a flock; i.e. pasture it; intransitively, to graze; generally to rule; by extension, to associate with (as a friend)
the sheep
tso'n (tsone)
from an unused root meaning to migrate; a collective name for a flock (of sheep or goats); also figuratively (of men)