Saarinen points out, as did Bauckham, that when Jude discusses OT and deutero-canonical texts discussing God's judgment (vs. 5, 9, 14), that Jesus is the one coming to judge. The move that Saarinen makes at this point is worth pointing out:
The Epistle of Jude performs its christological rearrangement of Jewish texts in a manner that is clear and provocative. The Lord, who saved a people out of Egypt and will come to execute a judgment on all, is Jesus Christ...When Jesus Christ is portrayed as a judge in this manner, on the one hand, he takes the traditional roll of divine judge. On the other hand, due to the intracanoncial attribution, the very event of final judgment also receives new, christological aspects that reflect the new rule of the gospel. The theme of mercy exemplifies this new rule (pp. 220-1).Thus, Jude's merciful approach in dealing with those who were straying receives its impetus from the christology underlying his argument. Jesus is the divine, merciful judge, and like him, our primary posture should be one filled with mercy, extending the hand of grace and love to the straying.