Like their ancestors they were disloyal and faithless, as unreliable as a faulty bow.
NIV
But they turned back and dealt unfaithfully and treacherously like their fathers; they were twisted like a warped and deceitful bow [that will not respond to the archer's aim].
AMP
But turned back, and dealt unfaithfully like their fathers: they were turned aside like a deceitful bow.
KJV