The severity and universality of the tenth plague, its manner of accomplishment by a direct act of God instead of by Moses' staff...and the unique celebration of the tenth plague as a lasting ordinance underscore the importance of the event in Old Testament Theology (OTT, 381).
This schema of 3+3+3+1 appears to form the basis of the plague series found in the book of Revelation. Paralleling itself to the plagues in Exodus, Revelation takes on a similar framework in the seven seals, trumpets, and bowls, where the three sets of three have become three sets of seven culminating in the smiting of the nations.
the letter d was omitted by haplography from the text that originally read prdt from the verb prd "to separate" in the Hiphil (EBC)
Now judgement is upon this world, now the ruler of this world is cast out.