Vincent's NT Word Studies
36. When the voice was past (en tw genesqai thn fwnhn). Lit., in the coming to pass of the voice. Rev., when the voice came, with A.V. in margin.37-43. Compare Matt. xvii. 14-21; Mark ix. 14-29.
Robertson's NT Word Studies
9:36 {When the voice came} (en toi genesqai ten fwnen). Another example of Luke's idiom, this time with the second aorist middle infinitive. Literally, "on the coming as to the voice" (accusative of general reference). It does not mean that it was "after" the voice was past that Jesus was found alone, but simultaneously with it (ingressive aorist tense). {Alone} (monos). Same adjective in #Mr 9:8; Mt 17:8 translated "only." Should be rendered "alone" there also. {They held their peace} (esigesan). Ingressive aorist active of common verb sigaw, became silent. In #Mr 9:9; Mt 17:9, Jesus commanded them not to tell till His Resurrection from the dead. Luke notes that they in awe obeyed that command and it turns out that they finally forgot the lesson of this night's great experience. By and by they will be able to tell them, but not "in those days." {Which they had seen} (hwn hewrakan). Attraction of the relative ha into the case of the unexpressed antecedent toutwn. Perfect active indicative hewrakan with _Koin_ (papyri) form for the ancient hewrakasin changed by analogy to the first aorist ending in -an instead of -asin.