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; (1 Chronicles 10:13)
This statement is not found in Samuel. It is characteristic of the writer of Chronicles, who constantly moralizes on the terrible effects of transgression and the blessings of righteousness.
Which he kept not.
Saul’s great sin was disobedience to the Lord’s commands (see 1 Sam. 13:13).
A familiar spirit.
Having failed to give heed to the Lord, Saul turned to a medium to ask guidance and counsel of demons (see on 1 Sam. 28:7-20).