The Midrash and Yerushalmi refer to tzedaka as stam “mitzvah”. R’ Tzadok offers two reasons for this: 1) Each particular mitzvah “corrects” a specific aspect of Creation. Only tzedaka, however, brings about a global uplifting of the entire world because it does not effect just a part of the person (e.g. tefillin relates specifically to the arm), but effects the entire person who is a microcosm of reality. 2) Tzedaka is ingrained in the Jewish persona – no matter how far a Jew has strayed, he/she is apt to perform some charitable act in their lifetime that reflects their Jewish roots. Chazal tell us that Avraham, the paradigm of chessed, stands at the threshold to Gehennom waiting to pull back any Jew who falls there, for every Jew has some merit of charity.
With this idea we can perhaps explain why Rashi focuses on Lot’s merit in not revealing that Avaraham and Sarah were husband and wife but does not mention Lot’s hachnasas orchim. A Jew does not become a ba’al chessed because he/she does a lot of charitable acts; a Jew is born a ba’al chessed almost as a genetic aspect of his/her personality. However, Chazal (Baba Basra 10) tell us “chessed l’umim chatas”, the chessed of non-Jews is not ingrained in their personality, but a non-Jew becomes a ba’al chessed because he/she engages in acts of charity. The difference is these acts are considered to always be tainted by ulterior motive (Michtav M’Eliyahu I:191), even something as subtle as responding to the emotional need to do good. For this reason, a Jew who pledges tzedaka on the condition that his child be healed is considered a tzadik, as he/she would have given the money anyway, but the same assumption is not make about a non-Jew (Tos Pesachim 8b). The gemara (B.B 4) tells us that Daniel was punished for advising Nevuchatnezer to perform tzedaka to aver an decree against him. At first glance this is hard to understand – if tzedaka would make Nevuchadnezer less of a rasha, then why would there be any objection to it, and if he would be guilty despite his charitable acts, why should the decree against him be mitigated? Perhaps the explanation is that the superficial act of charity does weigh in a person’s favor, but where chessed l’umin chatas the core of the person remains the same. The superficial covering over of sin is not something to strive for. Various Midrashim contrast the wickedness of Sdom with that of Yerushalyim at the time of the churban – in both cases people engaged in Avodah Zarah, murder, and licentious relationships, but Yerushalyim is credited with fulfilling tzedaka (Sanhedrin 104), while Sdom’s fate was ultimately sealed because they did no charitable acts (Ch. haRan Sanhedrin 56b). It is not the superficial act of charity which is the distinction, but the underlying personality – a Jew, even one who engages in the most vile behavior, is still assumed to have a core the descends from Avraham and marked as a ba’al chessed. Lot may have engaged in acts of chessed, but these acts did not form the core of his personality. When push came to shove, it was the simple act of silence that saved Avraham which was considered his greatest merit.