The first occurrence.
I have waited for Your salvation, O YHVH. Gen 49:18
The primitive root.
yud י = the closed hand, thus work, throw, worship
shin ש = two front teeth, thus sharp, press, eat, two, again
ayin ע = the eye, thus watch, know, shade
The story: Actively (yud) and sharply, diligently (shin) watching out (ayin) for danger. We have carried over this same understanding in English from the Hebrew mother tongue, when we say, “Look sharp!” to mean, Look carefully without letting anything escape your notice. The concrete noun in between the verb form “to save” and the abstract concept of “salvation,” is “shepherd,” one who rescues his flock.
The shepherd carefully watches over the flock and the surrounding area always on the lookout for danger. When a predator comes to attack, the shepherd destroys the enemy. – Ancient Hebrew Lexicon