It happened, And as they were parting from him,[a]that Peter said to Jesus, “Master, it is good auspicious for us to be here. Let’s—we should make three tents: one for you, and one for Moses, and one for Elijah,” not knowing what he said is saying.
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a Gr. ἐγένετο ἐν τῷ διαχωρίζεσθαι αὐτοὺς ἀπ’ αὐτοῦ is functionally equivalent to a genitive absolute.
Kata Biblon