כל המצוה אשר אנכי מצוך היום תשמרון למען תחיון ורביתם ובאתם וירשתם את הארץ…(עקב ח:א)

The word “תשמרון” means to wait and to hope, as we find (פרשת וישב) that when Joseph was telling his dreams to his father and his brothers, it says “ואביו שמר את הדבר” – and his father waited for his word, hoping that only good will come out of it.  

This could explain our passuk commanding us to wait and hope to be able to perform all commandments: 

כל המצוה – all the mitzvos – commandments that Hashem commanded, 

תשמרון – we should wait and hope for the opportunity when we will be able to fulfill them. 

For example, the mitzvos that are “תלויות בארץ” – dependent on being in Eretz Yisroel, which one cannot perform when living in Diaspora – we have to wait and hope for a time when we shall be able to fulfill them.