Act 4, Scene 1: Shylock rejoices of Portia, "a Daniel! O wise young judge." This is alluding to the biblical story of Daniel and Susanna; how can this statement be ironic?

Daniel, in the Bible, saves Susana from being killed by imploring the authorities to question the old men who accused her of lechery. Shylock seems to agree with Portia as long as it seems she is supporting his case. This will become quite different as the case goes on.