I can of myself do nothing. As I hear, I judge, and my judgment is righteous; because I don't seek my own will, but the will of my Father who sent me.
And He begins to talk to them now, emphasizing what He's saying with these words verily, verily. And the repetition of the word is for emphasis, it's, "Alright, now hear this." I mean, it's really calling their attention to what I'm about to say.