1 Chronicles 10:13

13 So Saul died on account of his sin which he had sinned against Yahweh concerning the command of Yahweh that he did not keep. He also consulted a medium to seek [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 When all Jabesh-Gilead heard all that the Philistines had done to Saul,

12 every strong man arose and took the dead body of Saul and the dead 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 on account of his sin which he had sinned against Yahweh concerning the command of Yahweh that he did not keep. He also consulted a medium to seek [guidance].

14 But he did not seek Yahweh. So Yahweh put him to death and turned over the kingship to David, the son of Jesse.