What would have happened if not for his Emunah?
Rashi: The false witnesses would have stood against me and finished me off.
Radak: I would have perished due to their words, if not that I trusted in You and was not concerned for their words.
Malbim: The false witnesses would have overcome me, if not for the merit of my Emunah.
In what did he believe?
Radak: I have hope in Hashem and I will see His good in "Eretz Chayim", i.e. the world to come.
Malbim: Hashem promised kingship to me. I believed that I will [get it, and] return to Eretz Chayim, i.e. Eretz Yisrael.
Why are there dots over "Lulei"?
Rashi, Radak (from Brachos 4a): David told Hashem, 'I know that You pay a good reward to Tzadikim in the World to Come, but I am unsure whether I will have a share among them. Perhaps I will lose my portion due to sin!'
What is "Eretz Chayim"?
Radak: It is the world to come. It is called Eretz, even though the Neshamah does not have a place, for the good of the world to come is metaphorically compared to Gan Eden 1 , which was the best place in the land. It is called Eretz Chayim, for when Adam was expelled from there, death was decreed on him.
Malbim: It is Eretz Yisrael.
Radak: Similarly, judgment of Resha'im is called Gehinom, which is a despised place near Yerushalayim where they cast Tum'os and Neveilos. There was a constant fire there to burn them, so it is a metaphor for Resha'im's punishment.
