Who is the Shomer?
Rashi (from Sanhedrin 94a): It is Hashem.
Radak: It is a guard of the city.
Malbim: It is the one whom Edom left to guard their land
What is the meaning of "Asa Voker"?
Rashi: Hashem says, it is upon Me to illuminate, to make morning for you.
Radak (12, citing his father): The Navi answers, the days and nights of Dumah finished; the morning of its fall came. Go against them, and you will succeed!
Malbim: Do not say that a thief came at night, and fled when light of morning came. Morning came, and it is still night (darkness and great affliction). The enemy plunders also during the day.
Why does it say "v'Gam Laylah"?
Rashi (Sanhedrin 94a) #1: Morning (the redemption) is coming, but after there is still much Galus first.
Rashi (Sanhedrin 94a) #2: Alternatively - redemption is coming, i.e. the second Beis ha'Mikdash will be built, but another Galus will follow.
Rashi (Sanhedrin 94a) #3: There is reward for Tzadikim, and punishment for Resha'im.)
Rashi: There is night for Esav, at the time of the deadline [for redemption].
Radak: The Shomer says, morning is coming, but it will not help you, for also night will come after , and you will need to guard from fear of the enemy!
Radak (11): Refer to 21:11:5:2.
Why does it say "Im Tiv'ayun Be'ayu"?
Rashi: If you will make your request, to hasten the Ketz.
Malbim: If you seek the enemy, "Shuvu Esayu" (return to your land, and you will find him there)!
What is the meaning of "Shuvu Esayu"?
Rashi: Repent in Teshuvah!
Radak: You will return to ask on other nights, for you have no security from the enemy.
Malbim: Refer to 21:12:4:2.