What is "Fole'ach"?
Rashi: It is cleaving [wood], like "Yefalach Kilyosai" (Iyov 16:13) [Radak - and "va'Yfalach El Sir ha'Nazid" (Melachim II, 4:39)
Why does it say "u'Voke'a ba'Aretz"?
Rashi: So our bones were scattered to reach the door of death, due to the evil of sinners.
Radak: The matter is repeated in different words.
Why does it say "Nifzeru Atzameinu Lifnei She'ol"?
Radak: Just like one who cleaves wood, the pieces scatter here and there, so we were close to death. "Our bones were scattered" is an exaggeration; from great fear, the body trembles, until it seems that the bones separate from each other - "v'Hispardu Kol Atzmosai" (22:15). "Atzameinu" (plural) refers to the bones of David and the men with him.
Malbim: David and his men were on the height of the mountain. They planned that if Sha'ul and his men will reach them, they will jump from the mountain to the path that descends from the mountain, and from there to the Midbar. This jump is dangerous, lest their bones [come apart and] be scattered! They trusted in Hashem to save them from the danger.
