How long (ew pote). "Until when." Cf. Matthew 7:17 ; John 10:24 . O Master (o despoth). Nominative articular form, but used as vocative (despota) as in Revelation 4:11 ( John 20:28 ). On despoth (correlative of doulo) see Luke 2:29 . Here (alone in the Apocalypse) it is applied to God as in Luke 2:29 ; Acts 4:24 , but to Christ in Jude 1:4 ; 2 Peter 2:1 . The holy and true (o agio kai alhqino). See Revelation 3:7 for these attributes of God. Avenge our blood on them that dwell upon the earth (ekdikei to aima hmwn ek twn katoikountwn epi th gh). This same idiom in Revelation 19:2 and see it also in Luke 18:7 , "a passage which goes far to answer many questions in theodicy" (Swete). We find ekdikew, late compound, used with ek as here in Deuteronomy 18:19 ; 1 Samuel 24:13 , but with apo in Luke 18:3 . For epi th gh (upon the earth) see Revelation 3:10 .