What does the Bible say about Saul's rejection as king?

In 1 Samuel 15, God instructs Saul to destroy the Amalekites for their historical sins against Israel. Saul, however, disobeys by sparing King Agag and keeping the best livestock for sacrifice, contrary to God's command (1 Samuel 15:1-9). As a result, God regrets making Saul king and announces his rejection of him as king due to his disobedience (1 Samuel 15:10-23). This account emphasizes the importance of obedience to God's will, highlighting that God desires obedience over sacrifice.