Eating expired soup is okay and will not harm you as long as the expired soup is not actually spoiled.
Expiration dates on the soup just means the soup is not at it's freshest and the taste can change and it's best to eat the soup before expiration date.
Expiration dates do not mean the soup is actually spoiled or bad to eat.
However if the soup expired and actually smells bad, smells sour, tastes bad or has mold growth in the soup then throw it out as it could make you sick.
If you eat the spoiled soup that has expired then you will likely get a stomach ache, stomach cramping, vomiting and maybe diarrhea.
In rare cases you could get really sick and die but the worst that would happen is you get simple food poisoning that will go away within a few days to a week.
But if you're in doubt about the soup or other food being good past it's expiration date it's best to just throw it out and not risk your health.