The Aramaic name Barabbas means 'son of the father' (bar = son; abba = father). He was a notorious prisoner — a rebel and murderer — whom Pilate released instead of Jesus at the Passover custom of releasing one prisoner. The crowd chose Barabbas, and Jesus, the innocent Son of the Father, was condemned.
The Barabbas exchange is one of the most theologically dense events in the Passion narrative. An innocent man (Jesus) was condemned so that a guilty man (Barabbas) could go free. This is the gospel in miniature — substitutionary atonement dramatized in history. Every believer stands in the place of Barabbas: guilty, condemned, set free because Another took our place. The irony of his name — 'son of the father' — while the true Son of the Father was condemned in his place is striking.