For the Amalekites and the Canaanites [are] there before you,.... Having removed from the valley, Numbers 14:25; or else had detached a party to defend the pass on the top of the mountain, and where perhaps they designed to feign a retreat if they found it proper, and draw them into a combat in the valley:
and ye shall fall by the sword: by the sword of the Amalekites and Canaanites:
because ye are turned away from the Lord: from the word of the Lord, from hearkening to and obeying his command:
therefore the Lord will not be with you; the consequence of which must be bad for them.