I mark the hours, every one. Nor have I yet outrun the sun. My use and value unto you...?

Question

What does this mean?

I mark the hours, every one. Nor have I yet outrun the sun. My use and value unto you, are ganged by what you have to do.

Some of you may know where this is from, but explain this to me, please.

Answer 1

It's what is enscribed onto Hermione Granger's time turner in the Harry Potter books.

It's really simple, it means this:

This time turner keeps every hour in past marked but can't go forward (Nor have I yet outrun the sun). The time turner is useful only if you know what you have to do when using it (Basically, use it only if yo have a plan).