The ship bears souls newly arrived in Purgatory. This arrival contrasts with the ferrying of damned souls into Hell in Dante’s
Inferno; while those souls arrived individually, weeping and cursing, these souls arrive singing in unison—suggesting that the journey toward salvation is communal, marked by fellowship, and that all of these souls have hope because they will eventually get to Heaven. The song they sing is Psalm 114, “When Israel went out of Egypt…”