Avos 5:16

If a love depends on something, then when that thing vanishes, the love will end. If a love doesn’t depend on anything, then it will never end. An example of a love that depended on something was Amnon’s “love” (which turned out to be lust) for Tamar. An example of a love that didn’t depend on anything was the loving friendship between David and Jonathan.

Avos 5:17

Any dispute that is for the sake of Heaven will ultimately prove worthwhile but a dispute that is not for the sake of Heaven will prove not to be worthwhile. An example of a dispute that was for the sake of Heaven is the halachic debate between Hillel and Shammai. An example of a dispute that was not for the sake of Heaven is the rebellion of Korach and his followers.