The חטא אדם הראשון created the possibility of רע. After we received the Torah that was erased and all we could do was good. The came the חטא העגל which recreated the possibility of רע and the לוחות were smashed [i.e. we lost מתן תורה]. That is שבעה עשר בתמוז.
The חטא המרגלים actualized the possibility of רע. That happened on Tisha B'av. Because of the latter חטא we were not זוכה to see the "ארץ אשר אראך". Our journey to the TRUE Promised Land as given to Avraham was interrupted. The word רע means broken or interrupted [as in "תרועם בשבט ברזל" and - "רֹעָה הִתְרֹעֲעָה הָאָרֶץ"]. The word טוב is what lasts and is completed [see Bava Kamma 55a].
בין המצרים [called by English speakers "The Three Weeks"] is when we are stuck in between these two sins.
To await the Geulah is to realize that what is we will have is NOTHING like what we have today.
ודוק.
Expansion on these ideas, here.
