What does 'that' refers to here?
At first glance, perhaps. The problem with the method employed is that there is a long list of other expressions that occur multiple times in Matthew (brood of vipers, wailing and gnashing of teeth, little faith are three), and less often in Luke, and only where Matthew has it in a parallel location. And those expressions are far more striking and unusual (not found elsewhere in the NT) than the less Hellenized spelling of Jerusalem, and we can account for Matthew having used that in other ways.1)
I also think that Matthew's use of Ἰερουσαλήμ seems, at first glance, to be a good argument for his dependence on Luke. On the other hand, Paul proves that different usage can be meaningful and intentional, and Matthew could theoretically have intended it as well. This is less likely, but still quite possible.
I was trying to make the point up thread that Luke was not being consistent, or perhaps he was being consistent within some system, but we have not yet figure out what that system is yet. Wienert (as quoted up thread) think he was being consistent in using sources in Acts, but since we don't know what those sources were, that doesn't help us.The problem, imho, is that Luke isn't consistent either. In chapter 13 this could be explained with the difference between direct speech and indirect narrative. But in chapter 19 there seems to be no reason why Luke could have used the two different spellings meaningfully and consciously. Verses 11 and 28 have the same context and indirect narrative.
You mean 13.34-35 is an appears a reception of Mark 11.11? I'll have to think about that. I think Luke is revealing that Jesus knew the course of his earthly mission in advance (in the way he does in John). That may result in Jesus being safe in Galilee (for his hour had not yet come), but I do not think that was the reason Luke put it where it is.Luke 13
22 He went on his way through towns and villages, teaching and journeying toward Jerusalem (Ἰεροσόλυμα)
33 Nevertheless, I must go on my way today and tomorrow and the day following, for it cannot be that a prophet should perish away from Jerusalem (Ἰερουσαλήμ). 34 O Jerusalem, Jerusalem, (Ἰερουσαλήμ Ἰερουσαλήμ) the city that kills the prophets and stones those who are sent to it! How often would I have gathered your children together as a hen gathers her brood under her wings, and you were not willing!
Luke 19
11 As they heard these things, he proceeded to tell a parable, because he was near to Jerusalem (Ἰερουσαλὴμ), and because they supposed that the kingdom of God was to appear immediately.
28 And when he had said these things, he went on ahead, going up to Jerusalem (Ἰεροσόλυμα).
2)
The meaning of the logion is somewhat unclear. The person speaking here is obviously not the earthly Jesus, but rather God in the form of the earthly Jesus ("How often would I have gathered your children together as a hen gathers her brood under her wings, and you were not willing!"). The word “Lord” in Matthew 23:39/Luke 13:35 should probably make the reader think of the enthroned Christ (”Blessed is he who comes in the name of the Lord!”)
It probably demands that the "Jews" should accept the Christian confession and Christian preachers ("... until you say, 'Blessed is he who comes in the name of the Lord!'"), but looks back at the murders of the OT-prophets.
The whole logion appears as a reception of Mark 11:1-11, but with a view to a much later present. Imho it fits more into Matthew's context, but seems to have been invented independently of that context.
Luke used the logion primarily as a theological explanation of why Jesus was still safe in Galilee. But then the direct speechs “Jerusalem, Jerusalem” and “you” don't fit there at all (Luke 13:31 "At that very hour some Pharisees came and said to him, “Get away from here, for Herod wants to kill you.")
The lament over Jerusalem does seem to fit better in its context in Matt 23, where Jesus is in Jerusalem and has been addressing the teachers of the law and Pharisees.
Best,
Ken