Part of the argument of "Oh, think not I am faithful to a vow" is summed up in the line "Were you not lovely I would leave you now."
While the argument of "Love is not blind" is
"Well I know
What is this beauty men are babbling of;
I only wonder why they prize it so."
Which reminds me of a quote that I thought was by Heine but now cannot find a source for:
"Why should I be always of my own opinion?"
Can anyone offer other such pairs of poems? A source for my quote?