Albert Barnes Commentary 1 Kings 9:6

"But if ye shall turn away from following me, ye or your children, and not keep my commandments and my statutes which I have set before you, but shall go and serve other gods, and worship them;" — 1 Kings 9:6 (ASV)

At all turn - Rather, If ye shall wholly turn from following Me (see 2 Chronicles 7:19). The Israelites were not to be cut off, except for an entire defection.