Kommentar zu Dewarim 3:23

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.

AND I BESOUGHT THE ETERNAL AT THAT TIME, SAYING. [The time referred to, is] when Moses mentioned the conquest of the lands of Sihon and Og. He said, And I commanded Joshua at that time,¹Above 3:21. intimating, that “I [Moses] will not go over there, for I besought the Glorious Name²Further, 28:58. [to rescind the decree forbidding me to enter the Land], but He hearkened not to me and He commanded me to charge Joshua, for he shall go over before this people.”³Verse 28 here.
The purport of the expression at that time is that it alludes to the time of the decree that he mentioned, Also the Eternal was angry with me [for your sakes, saying: ‘Thou shalt not go in thither’],⁴Above, 2:37. though [Moses’] supplication is not mentioned there on the day of that event. The correct interpretation, however, is that the expression at that time refers to the time mentioned: “when I conquered Sihon and Og and I began to war against the nations given to Israel and I allocated the land to the two tribes [Reuben and Gad].” In that case, this supplication [referred to here] was offered when it was said to Moses, Get thee up into this mountain of A barim,⁵Numbers 27:12. for it was then that he sought mercy in the matter and entreated this supplication. And when G-d did not hearken to his voice, he again prayed, Let the Eternal, the G-d of the spirits of all flesh, set a man over the congregation,⁶Ibid., Verse 16. as is mentioned there. It is this verse, And charge Joshua³Verse 28 here. [that constitutes the answer to Moses’ second request]. Now, there [in the Book of Numbers] Scripture mentioned the prayer on which he was affirmatively answered [namely, the appointment of a successor]⁷Ibid., Verses 18-21. and here he mentioned this [unsuccessful prayer] in order to inform the people that, although the Land was beloved to him, he did not merit [to enter] it because of them. All this was part of his reproof.

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…