What is "mi'Bor Sha'on"?
Rashi: From bondage in Egypt, and from Sha'on (the clamor of) the sea.
Radak: It is a pit with much water. This is like "ki'Sh'on Mayim Kabirim" (Yeshayah 17:12). "Bor" is a metaphor for their illness. Just like one who falls in a pit fears lest he drown in its water or mud, so a Choleh fears lest he die from his illness.
Malbim: It is a pit full of raging, rising water.
What is "Tit ha'Yaven"?
Rashi: It is the sea. Ha'Yaven is an expression of mud. Radak - Tit is Samuch to ha'Yaven, even though both of them mean the same, to teach all kinds of mud - thick and thin. This is like "Admas Afar" (Daniel 12:2).
Malbim: It is sticky mud (quicksand); one who falls there cannot rise from it.
Why does it say "va'Yakem Al Sela Raglai"?
Malbim: Not only did He raise me from the pit. He lifted me onto a fortress, a place where my enemies cannot reach.
What is the meaning of "Konen Ashurai"?
Rashi: He prepared my steps [Radak - when I ascended from the pit; I did not slip. I.e. my illness did not worsen.
Malbim: You established my steps there strongly.