What does the Bible say about unlawful sacrifice?

In 1 Samuel 13, Saul unlawfully performed a sacrifice by usurping the role of the priest, which was designated only for God's chosen representatives. This act demonstrated Saul's lack of faith and disregard for God's command, leading to God rejecting him as king. This account teaches that obedience to God's prescribed order is crucial, as deviation, even in seemingly good acts, can lead to judgment. Just as Saul's actions led to his downfall, believers today are called to respect the boundaries of authority God has set, particularly in worship and ministry.