MG Váetchánán

ואתחנן — All forms of the verb חנן signify an ex gratia gift. Although the righteous might make a claim to reward depend Upon their good deeds, yet they solicit from the Omnipresent only an ex gratia gift. [Because He had said to him, (Exodus 33:19) “I will show grace (וחנתי) unto him to whom I will show grace”, he (Moses) when referring to his entreaty of God uses the expression (lit., spoke to Him) "I implored grace (ואתחנן)” (Midrash Tanchuma 5:2:3] — Another explanation is that the idea of an ex gratia gift is not to be stressed; but this is merely one of the ten terms by which prayer is described, as are enumerated in Sifrei Devarim 26:7.

By which prayer is described, as is stated in Sifrei. The following [are the ten terms: 1.שועה. 2.צעקה. 3.נאקה (three types of crying out). 4.רנה (song). 5.פצור (press). 6.קריאה (call). 7.נפול (fall). 8.פלל (plead). 9.פגיעה (approach). 10.תחנה (supplicate).

I pleaded to Hashem. Rashi explains that even though the righteous can claim rewards based on their good deeds, they ask the Almighty only for an undeserved gift. This is difficult to understand, for why would one think that they would ask for reward based on the good deeds that they had already performed? A person can never have any claim that Hashem owes him, because all of the mitzvot that a person does can never be sufficient to pay Hashem back for all the goodness that He does…

The answer to this question is that when it says that the righteous can claim based on their good deeds it does not refer to those good deeds that they have already performed, but to those good deeds that they will do in the future. For it is understood that no righteous person wants to claim any physical benefit, except in order to be able to fulfill another mitzva… If so, Moshe could have based his request on those good deeds that he would do in the future if Hashem would grant him his request. This is something real.

לא תספו YE SHALL NOT ADD — For instance, to place five chapters in the Tephillin, to employ five species of fruit and plants in the fulfilment of the command of Lulab And to place five fringes on one’s garment. Thus, too, must we explain the following words ולא תגרעו, Ye shall not diminish [from it]" (Sifrei Devarim 82:4).

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'לא תוסיפו וגו, “do not add, etc.;” G–d implies that anyone adding to the words of the Torah,-however well meaning he may be,-will in fact detract from the value of the Torah. [If G–d is perfect, something that every believing Jew accepts as axiomatic, any addition to or deletion from His Torah would make it, ergo Him, imperfect. Ed.] For instance, when the Torah decreed 4 strings of tzitzit for the corners of a four-cornered garment, adding a fifth string would not only not make it holier, but would make it useless, and anyone reciting a benediction over such a tallit would desecrate the holy name of G–d by pronouncing such a benediction. The same reasoning applies to sitting in a sukkah for an extra day or adding another a fifth species to a lulav.

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