Final answer:
Saul goes against the 'Ban' by failing to fully execute God's command to destroy the Amalekites and sparing King Agag and the best of the livestock. He also kills innocent priests and consults a medium, which are considered to be going against God's commands.
Step-by-step explanation:
In the biblical book of Samuel, Saul, the first king of Israel, goes against the 'Ban' by failing to fully execute God's command to destroy the Amalekites and their possessions. In 1 Samuel 15:3, God commands Saul to completely destroy the Amalekites, sparing no one, including their men, women, children, and livestock. However, Saul disobeys and spares King Agag and the best of the livestock.
Additionally, Saul's actions in 1 Samuel 22:17-19 and 1 Samuel 28:7-25 involve him killing innocent priests and consulting a medium, which are also considered to be going against God's commands.
These actions ultimately lead to God rejecting Saul as king and choosing David as his successor.