If a righteous man turns from his righteousness and practices iniquity, he will die for this. He will die because of the iniquity he has committed.
KJV
When a righteous [man] turneth away from his righteousness, and committeth iniquity, and dieth in them; for his iniquity that he hath done shall he die.
ASV
When the righteous man turneth away from his righteousness, and committeth iniquity, and dieth therein; in his iniquity that he hath done shall he die.