What do we learn from "Yira'ucha Im Shemesh [v'Lifnei Yare'ach Dor Dorim]"?
Brachos 9b: Vatikin finish Shema at sunrise, in order to be Somech Ge'ulah to Tefilah (begin Shemoneh Esreh right after Ga'al Yisrael), and pray during the day
Brachos 29b: It is a Mitzvah to pray when the sun is red (sunrise and sunset).
Sanhedrin 99a: The days of Mashi'ach will be three generations. (Dor teaches one generation, and Dorim teaches another two.)
Rashi: Yisrael will learn to fear You all days of the sun and moon, for all generations. Radak - this is an exaggeration.
Radak #1: The suffix Chaf in "Yira'ucha" refers to Hashem. In the days of Shlomo, Yisrael feared Hashem.
Radak #2: If this refers to Mashi'ach, this is no exaggeration; the entire land will fear Hashem, forever!
Malbim: People will fear Hashem and constantly do His will, like the sun and moon rejoice to do His will without deviation. The fear will be fixed in their hearts.
Why does it say "v'Lifnei Yare'ach"?
Brachos 29b: This teaches that it is a Mitzvah to pray when the sun is red (at sunset).
Rashi: Yisrael will fear while the moon exists, and they are in front of it. This is like 'bi'Fnei ha'Bayis veshe'Lo bi'Fnei ha'Bayis' (Chulin 78a). Radak - Lifnei is like b'Od. The same applies to "Lifnei Ash" (Iyov 4:19), "Lifnei Shemesh" (below, verse 17).
What do we learn from "Dor Dorim"?
Refer to 72:5:1:3.
Radak: In his days they will learn to fear You, to the point that they will fear You all days.
Malbim: [Their fear] will persist for all generations, like the days of Shamayim over the land.
