In this parable, Jesus is speaking to the Jewish people, right then, in that moment. This wasn’t about the second coming or some future occasion.
The son came and was standing right there in front of them. They were His people. When He came to invite them to the Banquet, to the New Covenant, they were too busy. There was some future casting with regard to the destruction of Jerusalem which happened about 40 years after Jesus.
We are the descendants of the Gentiles, the people on the streets who were not initially on the guest list.
I think that part of the point of this parable is to remind us, similar to the workers in the vineyard, it is God’s banquet, not ours. It is not for us to say (to judge) who is or is not invited. And God has full discretion, based on His criteria, not ours.
I don’t think the bit about the undressed man is to tell us that God is going to arbitrarily decide to deny entry, rather to remind us that it’s still a banquet and we better show some respect. A banquet lasts for days and a lot of expense and preparation went into it, when you come, be dressed appropriately and ready to be fully present.
How often do we reduce God’s banquet to a quick trip through the drive through? Cheap grace can make you fat without ever filling you up.
Do you have time for the banquet?
And after you’ve accepted the invitation and notice there is still plenty of space and food, will you go out to the street corners and invite in the strangers?