King James Version
So Saul died for his transgression which he committed against the LORD, even against the word of the LORD, which he kept not, and also for asking counsel of one that had a familiar spirit, to enquire of it;English Standard Version
So Saul died for his breach of faith. He broke faith with the LORD in that he did not keep the command of the LORD, and also consulted a medium, seeking guidance.New International Version
Saul died because he was unfaithful to the LORD; he did not keep the word of the LORD and even consulted a medium for guidance,