‘But they cried out all together, saying, “Away with this man, and release to us Barabbas (one who for a certain insurrection made in the city, and for murder, was cast into prison).'
The chief priests' men had been at work among the crowds who, knowing that a prisoner was due to be released according to Jewish custom (John 18:39), now called out as one that Barabbas be released to them and that Jesus should be sent to His fate. Barabbas was an insurrectionist awaiting execution for murder.
A first century Egyptian papyrus mentions a similar releasing of a prisoner by a Roman prefect as a result of popular demand. It is ironic that the name Barabbas can mean ‘son of the father' (and that his name may also have been Jesus - Matthew 27:16-17 in B Theta f1 Origen). They had had to choose between the false and the true.