The Romans who governed the Jews had a custom at Passover of releasing one prisoner chosen by the people. It happened that when Jesus was on trial there was another prisoner, a notorious revolutionary and murderer named Barabbas.
The Roman governor Pilate asked the Jews whether they wanted Jesus or Barabbas released, and they called for Barabbas. Their choice led to Jesus being crucified.
While Barabbas was a real person, readers have noted the symbolism of his name. It means “son of a father”—in other words, “anybody.”
So by literally dying in Barabbas’s place, the innocent Jesus was dying in the place of every “son of a father’—that is, in place of everyone.