The first occurrence.
Behold, I cry out of wrong, but I am not heard: I cry aloud, but there is no judgment. Job 19:7
The primitive root.
Strong’s H7768 שוע shava; a primitive root; according to Strong’s, properly meaning, “to be free;” but used only causatively and reflexively, meaning “to cry aloud” (for help, i.e. freedom from some trouble).
shin ש = two front teeth, thus sharp, press, eat, two, again
vav ו = the tent peg, thus add, secure, hook
ayin ע = the eye, thus watch, know, shade
The cognate words will help us find the story. One is “to watch over;” another is “shepherd.” When that which destroys (shin, in the sense of the teeth which rends its food) comes, the sheep remain secure (vav) when they cry out, for the shepherd keeps watch (ayin) over them to destroy the destroyer.