1)
When did they turn their heads away from Me?
1.
Malbim: It is when I came to return them to the good way.
2)
What is "Lamed"?
1.
Rashi: It is teaching [Radak - via the true Nevi'im].
3)
Why does it say "Hashkem v'Lamed"?
1.
Malbim: It was not only once, rather, constantly!
4)
Why does it say "Einam Shom'im"?
1.
Malbim: They do not even hear My words, for through hearing, they would learn a lesson - "Hashmen Lev ha'Am