Jesus used the phrase "Lord Lord" 5 times. Two are used in parables and two, which deal with final judgment at the close of the Sermon on the Mount and this use in Luke:
“Why do you call me ‘Lord, Lord,’ and not do what I tell you? (Luke 6:46) [ESV]
τί δέ με καλεῖτε κύριε κύριε καὶ οὐ ποιεῖτε ἃ λέγω [mGNT]
Since the word means "master" someone who calls a person "lord" should do what the master says. It seems odd to say a person would say "Lord Lord," and not do what they are told.
When Moses was told to go back to Egypt, he balked:
But Moses said to the LORD, “Oh, my Lord, I am not eloquent, either in the past or since you have spoken to your servant, but I am slow of speech and of tongue.” (Exodus 4:10)
Which in the LXX has a type of repetition of Lord:
And Moses said to the Lord, I pray, Lord, I have not been sufficient in former times, neither from the time that thou hast begun to speak to thy servant: I am weak in speech, and slow-tongued. (LXX)
εἶπεν δὲ Μωυσῆς πρὸς κύριον δέομαι κύριε οὐχ ἱκανός εἰμι πρὸ τῆς ἐχθὲς οὐδὲ πρὸ τῆς τρίτης ἡμέρας οὐδὲ ἀφ᾽ οὗ ἤρξω λαλεῗν τῷ θεράποντί σου ἰσχνόφωνος καὶ βραδύγλωσσος ἐγώ εἰμι
Does Jesus use the phrase "Lord Lord" in Luke as an allusion to Moses' reluctance to do what he was told?