VaEschanan el Hashem… Rashi explains that the word "va’eschanan" hints to Moshe requesting that his request be granted as a mantas chinam, a free gift, rather than in the merit of his mitzvos.
The Midrash (Shmos, parsha 40) comments on the pasuk, “V’chanosi es asher achon…” as follows:
Hashem showed Moshe all the treasure houses in shamayim and he pointed out who each one was for. “Here’s the treasure chest for those who do mitzvos. Here’s the treasure chest for those who raise orphans..." and so on and so forth, until they got to the biggest treasure chest of all.
“Who's that for?” asked Moshe.
“The other treasures,” said Hashem, “Were given to those who earned them. But for those who have nothing, I give them a mantas chinam of my treasure chest.”
“V’chanosi es asher Echon” – Hashem gives away a mantas chinam.
What kind of system is this? A guy spends his life doing mitzvos, learning Torah, helping others, and he gets a smaller reward than the guy who has nothing!?
The Shem m’Shmuel explains in the name of his father, the Sochatchover, that for those who pride themselves on the mitzvos they have done, large or small, the reward is the fruits of those mitzvos, and there is a treasure chest of appropriate size. But for those who come to shamayim and despite all that they have done, feel that they have accomplished nothing – for after all is said an done, how much has anyone really accomplished in comparison to what we owe Hashem – for these people, Hashem sets aside the greatest treasure of all, his mantas chinam.
Moshe could have asked Hashem to go to Eretz Yisrael in the zechus of his Torah, his avodah, his leadership of Klal Yisrael. But Moshe realized that after all is said and done, it’s all mantas chinam.