Which quotation from "The Tell-Tale Heart" by Edgar Allan Poe brings out the theme of time?

And this I did for seven long nights—every night just at midnight.

I made up my mind to take the life of the old man, and thus rid myself of the eye forever.

All in vain; because Death, in approaching him had stalked with his black shadow before him, and enveloped the victim.

It is impossible to say how first the idea entered my brain; but once conceived, it haunted me day and night.

And it was the mournful influence of the unperceived shadow that caused him to feel – although he neither saw nor heard – to feel the presence of my head within the room.