Malbim (5-6): He told them to repent from all their evil ways, and then Hashgachas Hashem would benefit them, and they would remain in Eretz Yisrael forever. If at least they will cease idolatry and to anger Me, I will not overtly benefit them, for they do other Aveiros, but I will not actively harm them. They will be subject to nature. If they [continue] to serve idolatry, I will do bad to them via Hashgachah.