In this quote, he is saying that only someone who has a deep understanding of the negative aspects of war can truly understand how to wage it effectively. In other words, knowledge of the harms and dangers of war is essential in order to be able to use it as a tool to achieve one’s goals.
Only a leader who is deeply familiar with the challenges and difficulties of running a business can truly understand how to profitability run it.
A business leader who has experienced the challenges and difficulties of running a business will have a deep understanding of these struggles, and will be better equipped to manage them when they arise. This is because first-hand experience with the obstacles and risks of business can provide valuable insight and knowledge, which can help a leader to identify and anticipate potential difficulties, and to develop strategies and actions to overcome them. As a result, a business leader who has experienced the struggles of business, and has a full understanding of them, will be better able to navigate these challenges and achieve success.