His withered fist still knocking at Death's door.

His drink, the running stream; his cup, the bare / Of his palm closed; his bed, the hard, cold ground.

So, in this way of writing without thinking,/ Thou hast a strange alacrity in sinking.

I kept knocking with my fist.

He has been back there knocking on the door and tonight he put it up front at the end.

We have been knocking on everyone's door. My knuckles are blue.