HELP - what does this quote mean? - the crucible

Im trying to look into this quote and explain the meaning behind it, but I have no idea?

For now I do think I see some shred of goodness in John Proctor. Not enough to weave a banner with, but white enough to keep it from such dogs.

Kia ora Charlotteneedshelp

This quote is about John Proctor finally seeing some goodness in himself toward the end of the play, after spending the whole play thinking that he is no good (because of his affair with Abigail etc primarily). Now, when he is being asked to confess falsely, he finds that he has more goodness than he at first thought - enough not to agree to a false confession.
“Not enough to weave a banner with” means that he knows he is not without guilt, and that he has done some bad things, but “white enough to keep it from such dogs” means that he has enough goodness not to go along with lies.

thankyou so much this helped a lot