Reference for Bava Kamma 158:4
ואלא גזלן היכי דמי אמר ר' אבהו כגון בניהו בן יהוידע שנאמר (שמואל ב כג, כא) ויגזל את החנית מיד המצרי ויהרגהו בחניתו
<i>And he plucked the spear out of the Egyptian's hand and slew him with his own spear</i>. R. Johanan said: Like the men of Shechem of whom we read:<span class="x" onmousemove="('comment',' Jud. IX, 25. ');"><sup>6</sup></span> <i>And the men of Shechem set liers in wait for him on the tops of the mountains, and they robbed all that came along that way by them: and it was told Abimelech</i>. Why did R. Abbahu not give his instance from this last source? He could say that since these were hiding themselves they could not be called robbers. And R. Johanan? — He could argue that the reason they were hiding themselves was so that people should not notice them and run away from them.<span class="x" onmousemove="('comment',' But not out of any fear. ');"><sup>7</sup></span>