...because of the decree of the Waters of Mei Merivah that "you shall not bring this congregation ito teh land" but God did not say that "you shall not come into the land" and Moshe thought that the decree against him was not a decree against him entering the land on his own, but was merely that he would not bring the community there as its leader and guide but someone else would guide them. Therefore after the war against Sihon, Moshe handed over leadership to Yehoshua...and then begin to pead with God saying "allow me to cross" that is to say, not that "I shall bring the nation over as their leader, just that I shall cross over as a civilian to see the land for this has not been decreed against me" and that is why Moshe says "at this time" meaning at the time when "I have already handed leadership to Yehoshua."
אָמַר רַבִּי אֶלְעָזָר: גְּדוֹלָה תְּפִלָּה יוֹתֵר מִמַּעֲשִׂים טוֹבִים, שֶׁאֵין לְךָ גָּדוֹל בְּמַעֲשִׂים טוֹבִים יוֹתֵר מִמֹּשֶׁה רַבֵּינוּ, אַף עַל פִּי כֵן לֹא נַעֲנָה אֶלָּא בִּתְפִלָּה. שֶׁנֶּאֱמַר: ״אַל תּוֹסֶף דַּבֵּר אֵלַי״ וּסְמִיךְ לֵיהּ: ״עֲלֵה רֹאשׁ הַפִּסְגָּה״.
Rabbi Elazar said: This story proves that prayer is greater than good deeds without prayer (Tosafot), as there was none greater in the performance of good deeds than Moses our teacher; nevertheless, his request was granted, albeit in a limited manner, in his request to enter Eretz Yisrael, only through prayer, when God permitted him to climb the mountain and look out over the land. As, initially it is stated: “Speak no more to Me,” juxtaposed to which is: “Go up to the summit of the mountain.”
This element of your prayer was granted to show the land to you.