How will we reconcile this Pasuk, which implies that immediately after Moshe's death they would pervert their ways with the Pasuk in Shoftim, 2:7, which states that they served Hashem throughout the lifetime of Yehoshua?
Rashi: This teaches us that a person's Talmid is as dear to him as he is to himself. Consequently, as long as Yehoshua was alive it was as if Moshe himself was alive.
According to one opinion in the Midrash Rabah, "Acharei" means a long time afterwards. 1
Refer to Bereishis 15:1:1:1 and the note there. Rashi answers for the other opinion (refer to 31:29:1:1)
Why did Moshe see fit to tell Yisrael that he knew that they would pervert their ways ... ?
Seforno: So that they would not ascribe their punishment to chance but to their sinful ways, and this would induce them to do Teshuvah. 1
Seforno: As in Yeshayah, 48:5.
