My dear brothers and sisters, today's readings remind us that Heaven awaits us as a party, not a chore. Everybody has to prepare for the party if they don't want to miss out on the fun.
In today's First Reading Isaiah describes our future as the ultimate party where shadows and tears are banished, and there's only room for celebration. Everyone, "all peoples," are invited to this celebration. No expense is spared on the food and the wine.
In today's Second Reading St. Paul reminds us that moments of famine help us appreciate even more the moments of feast. If you want just one list of all the ups and downs of St. Paul's missions, just read 2 Corinthians 11:21–33: prisons, beatings, shipwrecks, "in toil and hardship, through many a sleepless night, in hunger and thirst, often without food, in cold and exposure."
In today's Gospel, the wedding feast reminds us of Heaven, but also that although everyone is invited to the party, some, in the end, will not be found worthy to participate in it, and some won't want to participate in it at all.
Some had already been invited to the feast, and now servants were sent to tell them it was ready. Obviously, these invitees had a closer relationship with the king: they were invited to come and didn't feel obliged to come.
The invitees ask to be excused, but just gave excuses not to come: they'd known when the great dinner would be held and had made other plans. Some didn't even make excuses and just killed the messengers.
Abandoned by his friends, the king invited other members of his kingdom, but not on the basis of friendship, just by a benevolence a king owes his people.
If this parable speaks to us of Heaven, it's also a reminder that God is merciful and good, but in the end, we have to do our part, even a little, if we want to be saved. Salvation is not automatic.
The man with no wedding garment had no answer for the king's question: there was no excuse he could offer, and if the king was displeased, it means something was expected of that man that he didn't do.
That wedding garment symbolizes having done something to partake and appreciate the marriage feast. This poor man shows no signs of celebration whatsoever. Maybe he represents that Christian who goes through the motions all their life but never actually seeks to help himself or others to get to Heaven.
We have to give Our Lord something to work with. The man with no wedding garment managed to get to the banquet hall, but he didn't go far enough to stay.