אבות ה׳:ט״ז - ה׳:י״ז

Any love that is dependent on something transient: that does not last. When the thing that was the cause for that love perishes, the love will also perish. But any love that is not dependent on something transient, but rather on something lasting - for example, the love of the righteous men and the sages - never perishes. In the same way that the thing which is the cause of that love does not perish, so [too] does the love not perish.

the love of Amnon and Tamar: [which was] because of her beauty.

the love of David and Jonathan: [which was] to fulfill the will of their Maker. As Jonathan said to David, "You will be the king over Israel and I will be your second."

Every argument that is for [the sake of] heaven's name, it is destined (literally, its end is) to endure: That is to say that the [parties to] the argument are destined to endure and not perish, as with the argument between Hillel and Shammai, [whereby] neither the students of the School of Hillel nor the students of the School of Shammai perished. But Korach and his congregation perished. And I heard the explanation of “its end” is its purpose that is sought from its subject. And [with] the argument which is for the sake of Heaven, the purpose and aim that is sought from that argument is to arrive at the truth, and this endures; like that which they said, "From a dispute the truth will be clarified," and as it became elucidated from the argument between Hillel and Shammai - that the law was like the school of Hillel. And [with] argument which is not for the sake of Heaven, its desired purpose is to achieve power and the love of contention, and its end will not endure; as we found in the argument of Korach and his congregation - that their aim and ultimate intent was to achieve honor and power, and the opposite was [achieved].