Deuteronomy 31 Afflictions suffered due to idolatry causes them to think the Almighty abandoned them

Deu 31:18
"But I will surely hide My face in that day because of all the evil which they will do, for they will turn to other gods.

The afflictions they will suffer due to their idolatry will cause them to think that the Almighty has abandoned them. Keep in mind that they (in the future) did not totally abandon worshipping Elohim, they just went into idolatry also. Elohim says that is totally unacceptable.