1 Chronicles 10:13

13 So Saul died for his unfaithfulness; he was unfaithful to the LORD in that he did not keep the command of the LORD, and also consulted a medium, seeking guidance,

1 Chronicles 10:13 Meaning and Commentary

1 Chronicles 10:13

So Saul died for his transgression
(See Gill on 1 Samuel 31:13) A violent and dishonourable death, which was suffered on account of the sins he was guilty of:

one was, which he committed against the Lord, even against the word of
the Lord, which he kept not;
both in not staying for Samuel the time appointed, and by sparing the Amalekites whom he was bid to destroy, ( 1 Samuel 13:13 1 Samuel 13:14 ) ( 1 Samuel 15:3 1 Samuel 15:9 )

and also for asking counsel of one that had a familiar spirit, to
inquire of it;
what he should do with respect to engaging in battle with the Philistines, ( 1 Samuel 28:8 1 Samuel 28:15 ) which to do was contrary to an express command of God, ( Leviticus 19:31 ) .

1 Chronicles 10:13 In-Context

11 But when all Ja'besh-gil'ead heard all that the Philistines had done to Saul,

12 all the valiant men arose, and took away the body of Saul and the bodies of his sons, and brought them to Jabesh. And they buried their bones under the oak in Jabesh, and fasted seven days.

13 So Saul died for his unfaithfulness; he was unfaithful to the LORD in that he did not keep the command of the LORD, and also consulted a medium, seeking guidance,

14 and did not seek guidance from the LORD. Therefore the LORD slew him, and turned the kingdom over to David the son of Jesse.