This is a familiar parable (though perhaps better known in the form it appears in Luke), in one sense easy to understand, and one we might instinctively apply simply to non-Christian friends rather than to ourselves. However, the opening verse makes it clear that the people Jesus particularly had in mind were the Pharisees, so once again I think we should be expecting it might well challenge us – the apparently keen and observant. And indeed the way the parable concludes makes it clear that there is a warning here not simply for those who blatantly reject Jesus, but also for those who apparently have responded to Jesus.
In the previous parable Jesus refers to himself as the landowner’s son, and as this parable speaks of a king’s son for whom a wedding banquet is being prepared it’s not hard to see the reference to himself: as his death approaches (now just days away) he seems to speak in his parables more and more openly about who he is. The preparations for the feast are lavish, the privilege of being invited is huge (imagine being invited to a royal wedding!), but the guests refuse the invitation: some seem simply apathetic – “they paid no attention” and had better things to do apparently – others are more obviously antagonistic and show their contempt for the king by their wanting nothing to do with his son. Either way they spurn the invitation to their loss.
But the king is determined that people should enjoy his lavish hospitality and honour his son. The banquet is opened to anyone who would come. The original guests are deemed undeserving (v.8), but not because there is some moral standard to meet because the “both good and bad” (v.10) are now invited to attend. The sting in the tail/tale comes in vv.11-14. The significance of the wedding clothes is not spelt out, but notice the man knows he is without excuse – he doesn’t try to plead that he didn’t own an appropriate suit but was told he could come, or that he had no time to go home and change. Quite clearly there should have been a change of clothes – grace does not remove the necessity of repentance. You might cross reference Matt.7:21-27. Some suggest that wedding garments would have been offered to the guests on arrival, and this person had spurned the offer, but that is not made clear. In a sense though he is shown to be like those who spurned the invitation initially (he faces a similar fate – excluded from the banquet and punished), for by refusing to wear the appropriate clothes he shows the same contempt for the son.
The parable therefore was a warning to Pharisees in Jesus’ day who were clearly rejecting Jesus, and it is a warning to modern Pharisees who might seem to have accepted the invitation, but whose lives show a similar rejection of Jesus.