But the people took of the spoil, sheep and oxen, the chief of the devoted things, to sacrifice to Yahweh your God in Gilgal.
Now he has shown a pattern of disobedience up to this point. He has become self-willed, doing his own thing. So the prophet is coming and warning him. This to me is very significant, because God does seek to warn us from our self-willed path of destruction. God doesn't just let you trip off into the path of destruction, without coming and giving you fair warning, oftentimes, repeated warnings.