Why Do Chessed?

What makes kindness "true"? Yaakov asks Yosef for chessed shel emes, and Rashi says that means kindness to the dead, who can never repay. Yet Tanach uses the same words for Eliezer, for Yaakov before meeting Esav, and for the spies promising to protect Rachav. And a Midrash has chessed and emes arguing on opposite sides over whether Adam should be created at all.The Rambam in Moreh Nevuchim, on what really changed after the Eitz HaDaas, turns the question back on you: why do you do chessed? A principal asks Rav Shteinman whether to accept a child into his cheder, and the reply comes in an unusually strong voice.