I can't see any reason why using the definite article with these nouns shouldn't be accepted, i.e.
"L'amour et la sagesse..."
It's because it's a saying and this apparently sounds better according to the people in the "œil pour œil" (An eye for an eye) lesson.
I don't understand why the articles are not used. Is it some special expression?
Same here. What's wrong with definite articles (even if it is idiomatic)
Again why are the definite articles dropped?
It's a tradition. With an adage, a French custom is to drop the article in front of noble abstract nouns. I think it sounds fancier and more impressive.
Je vais dire cela à ma femme !
L'amour est la sagesse
Can someone here explain to me the ne...pas rules in FRENCH?
Try this: https://www.cliffsnotes.com/study-guides/french/french-ii/french-ii-basic-verbs/negation