Mishnah 16 - Chapter 5 - Pirkei Avot

Kol ahavah shehi teluyah vedavar, batel davar, betelah ahavah. Veshe'einah teluyah vedavar, einah betelah le'olam. Eizo hi ahavah hatteluyah vedavar, zo ahavat amnon vetamar. Veshe'einah teluyah vedavar, zo ahavat david vihonatan.

All love that depends on a something, [when the] thing ceases, [the] love ceases; and [all love] that does not depend on anything, will never cease. What is an example of love that depended on a something? Such was the love of Amnon for Tamar. And what is an example of love that did not depend on anything? Such was the love of David and Jonathan.

All love which is contingent upon a passing thing — once the thing passes, the love passes; and (all love) which is not contingent upon a passing thing [like the love of tzaddikim and sages] never passes. What is love that is contingent upon a passing thing? The level of Amnon and Tamar, [Amnon loving Tamar because of her beauty]. And (what is love) that is not contingent upon a passing thing? The love of David and Jonathan [to fulfill the will of their Master. Jonathan said to David (I Samuel 23:17): "You be the king over Israel and I will be your viceroy."]