Q. Why does the Torah say that no-one knows Moses’ burial place?A. Probably in order to prevent a Moses cult developing, with an industry centred upon pilgrimages to his grave.
But there is an additional, homiletical argument – where is Moses buried? Wherever people ignore his Torah.
According to the Midrash (Kohelet Rabbah to 9:4), Hadrian said to Rabbi Yehoshua ben Chananiah, “I am greater than Moses, because he is dead and I am alive”. Rabbi Yehoshua retorted, “No, Moses is greater, because his word is obeyed and there is no guarantee that yours is!”
So, as long as people study Torah, Moses is alive, but wherever Torah is neglected, there Moses is buried.
Likewise, as long as people treasure the Psalms, David is alive; as long as people consult Rashi’s commentary, Rashi is alive. And as long as people recite Yizkor and say Kaddish, and quote their parents, their parents are alive.
We can all live forever if our children and future generations keep us standing beside them.