"战争是对人的终极考验在这种考验中他达到了其他任何活动中都无法企及的高度"

Simplified Meaning:

When people are in a war, they go through extremely hard and dangerous situations. War pushes them to their absolute limits, forcing them to show courage and strength they didn't know they had. Think about firefighters during a big fire. Usually, they do their job and face little fires, but when there's a massive, out-of-control blaze, they have to be braver, smarter, and faster than ever before. Similarly, in war, soldiers have to use all their skills and bravery to survive and protect others, reaching a level of heroism and effort not often needed in everyday life. This means that war brings out the very best and sometimes the most extraordinary levels of human ability and character. This can inspire someone to understand that, even in the toughest times, they have the potential to reach new heights and achieve incredible things by pushing through challenges.