I now looked this up in my bible of modern German, and again I notice that it is completely different from your English text. I wonder if it is just this particular edition I have or the German translation in general.
It says: Sie alle, die mich hassen und befeinden, bekommen meinen Zorn zu spüren! Ich schärfe jetzt mein Racheschwert, dann schlag ich zu und schaffe Recht.
It's much longer and there is nothing about repay or reward.
I'll check another edition on the weekend.