This passage seems like a legal loophole gone wrong, but look closer – God's plan is unfolding even in the chaos.
The entire scenario – the Passover feast, the custom of release, the presence of a notorious prisoner like Barabbas, and Pilate's attempts to free Jesus – was orchestrated by God's sovereign hand. Even though human hearts were filled with malice, envy, and political expediency, God used these flawed elements to fulfill His redemptive plan.
Pilate, trying to navigate a difficult political situation and convinced of Jesus' innocence, became an unwitting instrument in God's hands. The crowd's clamor and the chief priests' manipulation, rather than thwarting God's will, actually served to reveal the depth of human sin and the necessity of Christ's sacrifice. God allowed this 'custom' to be twisted into a tool for His ultimate salvation.