Luke 9:33

33 And when they were about to go away from him, Peter said to Jesus, Master, it is good for us to be here; let us make three tents, one for you and one for Moses and one for Elijah: having no knowledge of what he was saying.

Luke 9:33 Meaning and Commentary

Luke 9:33

And it came to pass, as they departed from him
That is, as Moses and Elias departed from Christ; or "when they began to depart", as the Syriac version renders it; or "would depart", as the Arabic and Persic versions; seemed desirous of going, or made some signal or other by which the disciples perceived they were about to go; for, as yet, they were not gone;

Peter said unto Jesus, master, it is good for us to be here, let us
make three tabernacles, one for thee, and one for Moses, and one for
Elias; (See Gill on Matthew 17:4)

not knowing what he said,
nor "what to say", as Mark observes, being in a surprise, and not in a situation to consider and weigh things well, whether what he said was right and proper, or not; (See Gill on Matthew 17:4)

Luke 9:33 In-Context

31 Who were seen in glory and were talking of his death which was about to take place in Jerusalem.

32 Now Peter and those who were with him were overcome with sleep: but when they were fully awake, they saw his glory and the two men who were with him.

33 And when they were about to go away from him, Peter said to Jesus, Master, it is good for us to be here; let us make three tents, one for you and one for Moses and one for Elijah: having no knowledge of what he was saying.

34 And while he said these things, the shade of a cloud came over them, and they were full of fear when they went into the cloud.

35 And there was a voice from the cloud saying, This is my Son, the man of my selection; give ear to him.