At the feast, Pilate offers to release ( apoluo ) a prisoner to the people.  Earlier in Matthew, the verb is used with some frequency to describe the release of a wife, a divorce (Matthew 1:19; 5:31-34; 19:3, 7-8).  In other passages, it means “send away,” as when the disciples wish to send away the crowds to get food for themselves (e.g., 14:15).

Though the word has a broader meaning, it seems plausible that the marital connotation is faintly present in the trial before Pilate.  The whole trial is a kind of anti-covenantal ritual.  The Jews refuse to acknowledge the king of the Jews; the Jews choose a brigand rather than their Christ; the Jews call down blood on them (as in Exodus 24) but it’s the blood of curse rather than the blood of the covenant.

As Sinai was the marriage of Yahweh with Israel, so in Pilate’s court, before the Roman governor, they initiate divorce proceedings.  The “released” one is Barabbas, but the one truly sent away is Jesus, Israel’s faithful Husband.