The world forgetting, by the world forgot? What does this mean?

Hi, I have a quote I don’t understand. Can you explain it for me?

“How happy is the blameless vestal’s lot!
The world forgetting, by the world forgot.
Eternal sunshine of the spotless mind!
Each pray’r accepted, and each wish resign’d”

I only understand the first line. ‘Blameless’ means innocent, ‘lot’ means one’s luck or situation in life, destiny. ‘Vestal’ is a female priest or goddess or something, I’m not really sure. So the first line means that how happy one would be if one is blameless, innocent, forgetful.

But I don’t understand the next 3 lines.

Can you explain them for me? Thanks in advance.

I get this quote from the movie “Eternal sunshine of the spotless mind.”

Yes, the first line states that an innocent pure woman is a happy one.

The second line is reinforcing the first, stating that the woman’s happiness is due to forgetting about the world’s woes, and being forgotten by the world. In other words, she neither worries about the world, nor does the world worry about her. She has forgotten, and has been forgotten.

The third line is again referencing forgetfulness, stating that a mind unclouded or spotted by memory is in eternal brightness, or sunshine.

The fourth line states that her every prayer has been accepted (her prayer is for forgetfulness), and that she’s given up all claims on any wishes she might have, save to forget.

In short, she is happy only because she has prayed for and received the gift of forgetting everything she’s been concerned about. There is an old adage that ignorance is bliss, and such is the case for this woman.

Incidentally, the words may come from the movie, but they are originally from a poem by Alexander Pope entitled “Eloisa to Abelard”.