In some Gospels, he received 30 silver coins for his actions, and later died by suicide after coming to regret the part he had played. (In the poem: "Where, bright and damned, the monstrous weight / Of thirty white coins lay.") The non-canonical Gnostic Gospel of Judas also indicates he may have engaged in the betrayal at Christ's own direction; this is also suggested in Cullen's poem.
Cullen's version of Judas in this poem clearly aims to humanize Judas and his actions, and underlines the possibility that Judas was acting at Christ's own direction and therefore might likely have achieved salvation. The larger picture is that of saintly devotion to Christ's demands -- even if the world may misintepret and come to "scorn your name."