1)
What is the meaning of "ha'Sam Nafsheinu ba'Chayim"?
1.
Radak: He kept us alive in Galus [Malbim - even though we were in great danger].
2)
In what sense did He not let us slip?
1.
Malbim: Via affliction, Yisrael repented, and did not slip more from Avodas Hashem.