They were [left], to prove Israel by them, to know whether they would listen to the commandments of Yahweh, which he commanded their fathers by Moses.
"The Israelites descended three steps in their cultural accommodation to paganism: (a) they lived among the Canaanites, (b) they intermarried with them, and (c) they served their gods. Each step is a natural one leading on to the next." [Note: Lindsey, p. 384.] 