“What have you done?” (13:11). King Saul demonstrated a lack of faith in God that proved very costly. God had commanded him to wait for the prophet Samuel to offer sacrifice before an important battle; however, when Saul had to wait longer than expected and his terrified troops started deserting him, and he decided that making the sacrifice himself would save the day (v11-13). Consequently, the prophet Samuel told him that his descendants would not inherit the throne.
“You have not kept the command of the Lord…” (v13). King Saul learned that winning on his terms, rather than God’s, meant losing everything. God is concerned with how we do things, not just the outcome of the battle.