Albert Barnes Commentary Job 30:12

"Upon my right hand rise the rabble; They thrust aside my feet, And they cast up against me their ways of destruction." — Job 30:12 (ASV)

Upon my right hand rise the youth - The right hand is the place of honor, and therefore it was felt to be a greater insult that they should occupy even that place. The word translated “youth” (פרחח pirchach) occurs nowhere else in the Hebrew Scriptures. It is probably from פרח pârach—meaning “to sprout, germinate, blossom”—and thus would mean “a progeny,” and would likely be applied to beasts.

Jerome translates it as “calamities;” the Septuagint as, “Upon the right hand of the progeny, or brood (βλαστοῦ blastou), they rise,” where Schleusner conjectures that βλαστοι_ blastoi should be read, meaning “On the right hand rise a brood or progeny.” Umbreit renders it, “eine Brut ... a brood.” Rosenmuller, Noyes, and Schultens concur. The idea, then, is that this rabble rose up, even on his right hand, like a brood of wild animals—a mere rabble that impeded his way.

They push away my feet - Instead of making way for me, they jostle and crowd me from my path. Once the aged and the honorable rose and stood in my presence, and the youth retired at my coming, but now this worthless rabble crowds along with me, jostles me as I go, and shows me no respect at all .

And they raise up against me the ways of their destruction - They raise up against me destructive ways, or paths that tend to destroy me. The imagery is taken from an advancing army that builds ramparts and other means of attack designed for the destruction of a besieged city. Similarly, they were constantly making advances against Job, pressing on him in a way designed to destroy him.