1 Samuel 15:23

For rebellion is as the sin of witchcraft
Or divination {e}, in whatsoever way it was exercised; for there were various sorts of it among the Heathens, and all condemned by the law of God, ( Deuteronomy 18:10 ) . Now rebellion against God, or disobeying his commands, though in things otherwise, were they not forbidden by him, lawful to be done, is as heinous a sin as to be guilty of witchcraft, or any kind of divination forbidden by the law of God, and deserves as sore a punishment:

and stubbornness is as iniquity and idolatry:
for a man, when he has committed a sin, to persist in it obstinately, or to vindicate himself in it, and insist on his innocence, which was Saul's case, is as hateful to God as any iniquity whatever; yea, as bad as idolatry, or making use of the teraphim, as is the word here; of which see ( Hosea 3:4 ) than which nothing is more abominable to the Lord:

because thou hast rejected the word of the Lord;
disregarded his command, treated it with contempt and abhorrence:

he hath rejected thee from being king;
not actually, for he continued to exercise kingly power and authority to his death, and was treated as a king by his subjects, and even by David, though anointed by the Lord; but the sentence of rejection was pronounced upon him, and the bestowal of the government on his posterity was cut off.