1)
Why does it say "Acharei Asher Heitiv Lachem"?
1.
Malbim: Since Hashem benefited you with Hashgachah through clinging to you, this obligates that if you abandon Him, He will do evil to you via Hashgachah. This is like it says (Amos 3:2) "Rak Eschem Yadati? Al Ken Efkod Aleichem Es Kol Avonoseichem."
