Birkas Hamazon Past Present Future

The third bracha, uvnei Yerushalayim, comes in the form of a request, racheim na—please have mercy. Just as the first bracha, hazan es haolam, acknowledges that we are completely dependent on G-d in the present, and the second bracha traces all past events to His activity, the third bracha points out that the future, too, is something we expect only from Hashem. Both our national and personal existence today, as well as the restoration of the Beis Hamikdash and kingship one day, are determined by Him.

Adapted from World of Prayer by Rabbi Elie Munk