1)
What was the request "Agurah v'Ahalecha Olamim"?
1.
Yevamos 96b: David requested that people should say teachings in his name in this world, for then his lips move in the grave.
2.
Rashi: Cause me to merit this world and the world to come.
3.
Radak #1: The verse discusses each Yisrael in Galus; I should dwell in the Beis ha'Mikdash a long time.
4.
Radak #2: The verse discusses David; I should dwell in the Ohel Mo'ed a long time. Malbim - he did not request success, only to be able to "dwell in Ohel Hashem and take shelter in the shade of His wings."