As they were departing from him (en twi diacwrizesqai autou ap autou). Peculiar to Luke and another instance of Luke's common idiom of en with the articular infinitive in a temporal clause. This common verb occurs here only in the N.T. The present middle voice means to separate oneself fully (direct middle). This departing of Moses and Elijah apparently accompanied Peter's remark as given in all three Gospels. See for details on Mark and Matthew. Master (Epistata) here, Rabbi ( Mark 9:5 ), Lord (Kurie, Matthew 17:4 ). Let us make (poihswmen, first aorist active subjunctive) as in Mark 9:5 , but Matthew 17:4 has "I will make" (poihsw). It was near the time of the feast of the tabernacles. So Peter proposes that they celebrate it up here instead of going to Jerusalem for it as they did a bit later ( John 7 ). Not knowing what he said (mh eidw o legei). Literally, not understanding what he was saying (mh, regular negative with participle and legei, present indicative retained in relative clause in indirect discourse). Luke puts it more bluntly than Mark (Peter's account), "For he wist not what to answer; for they became sore afraid" ( Mark 9:6 ). Peter acted according to his impulsive nature and spoke up even though he did not know what to say or even what he was saying when he spoke. He was only half awake as Luke explains and he was sore afraid as Mark (Peter) explains. He had bewilderment enough beyond a doubt, but it was Peter who spoke, not James and John.