The Gospel today brings up a very ancient doctrine of the Church, and the term for that doctrine is Divine Impassibility: It means that God does not change. In fact, as our own Anglican Article I teaches, he is "without passions." Some modern theologians object to this, and insist that the scriptures present to us an emotional God who makes up his mind by reacting to events. They see metaphorical language as literal, forgetting that God has revealed his word to our minds by use of our own language. Emotion includes motion, that is movement and change. But, God does not change.
The reaction to the king's kind invitation, bidding people to attend the wedding of his son, reminds me of the fifth seal in the Book of Revelation:
And when he had opened the fifth seal, I saw under the altar the souls of them that were slain for the word of God, and for the testimony which they held: And they cried with a loud voice, saying, How long, O Lord, holy and true, dost thou not judge and avenge our blood on them that dwell on the earth? And white robes were given unto every one of them; and it was said unto them, that they should rest yet for a little season, until their fellowservants also and their brethren, that should be killed as they were, should be fulfilled.- Rev. 6:9-11
When the guests who were invited snub him, and refuse his invitation, and then persecute the messengers of his gracious invitation to the death, the king becomes "wroth." His judgment falls on those murderers, and he sends his army to slay them. The word "wroth" is, of course, a form of the word "wrath." In many passages of scripture we read about the wrath of God. What is the wrath of God?
To answer that, we look at the image of God in this parable. The king represents God, and the invitation represents the proclamation of his mercy offered in the Gospel. The invitation is to attend "the marriage supper of the Lamb" (Rev.19:9), the marriage feast of the King's Son. The image in the parable includes the obvious implications of forgiveness of sin (purchased by that Son on the sacrificial altar of the cross, and his resurrection that destroys death), showing that the heart of the king is generous, benevolnet and gracious. "Taste and see that the Lord is good."
When the invited people refuse this kindness, and persecute his messengers, they incur his wrath. The king has not changed, the people have. His principles are solid and unmoving. His wrath comes from the same heart as his generosity. Of course, the wrath of God is not exactly like the wrath of this king, for the king is a man who changes due to emotion. The king in today's Gospel appears to be moved, sometimes by anger and sometimes by his own generosity. Unlike God, this king can be surprised, because he does not know all things before they happen. But, he is in the story only to represent God as an imperfect human illustration, a character who is metaphorical in nature. God's wrath is itself a metaphor. What it means is that you stand on one side of the line or the other, either accepting his kind and gracious offer in the Gospel of his Son, or you refuse that offer and side with the world, the flesh and the Devil. Because God never changes, you stand either on the side of "wrath" or on the side of mercy.
Look at the word that the king uses when he must have his "bouncers" kick out an impolite guest: "Friend, how camest thou in hither not having a wedding garment?" This word, "friend", seems rather odd. In fact, it means that this impolite guest, the one who refused the wedding garment (that is, refused the vestment handed out by the king's servants at the door) in a gesture of disrespect, was in some way beloved of the king. That is what it means that he was called "friend" (ἑταῖρος, hetairos). The same word is used later in this same Gospel (According to St. Matthew) when Jesus addresses the traitor Judas in the Garden of Gethsemane.
And forthwith he came to Jesus, and said, Hail, master; and kissed him. And Jesus said unto him, Friend, wherefore art thou come? Then came they, and laid hands on Jesus, and took him.-Matt. 26:50
What could better demonstrate that the Impassibility of God is consistent with the fact that God is love? (I John 4:8, 16) He does not change. Jesus loved Judas, even knowing that the man was a devil, the traitor, for whom it would have been good had he never been born. Jesus was not changed toward Judas, though Judas had renounced him, had abandoned his apostolic office to betray him to the death. "Friend, wherefore art thou come?"
The king casts the impolite and contemptuous guest out of his palace because that man had placed himself beyond the reach of the king's generous and gracious nature. The man did not need to buy some expensive garment, because it was the host of such a feast who provided these garments, outer garments or vestments, at the door. And, in polite society it was expected that a guest would put the garment on over his own clothes.
The night is far spent, the day is at hand: let us therefore cast off the works of darkness, and let us put on the armour of light. Let us walk honestly, as in the day; not in rioting and drunkenness, not in chambering and wantonness, not in strife and envying. But put ye on the Lord Jesus Christ, and make not provision for the flesh, to fulfill the lusts thereof. -Rom. 13:12-14
We are told to "put on Christ." But, first we are instructed to cast off the works of the flesh. Everything is provided for us. We put on Christ by hearing the word of God, remembering that in Hebrew the word for "hear" is the same word as "obey." We put on Christ by staying within his Church. We put on Christ by hearty repentance and true faith. We put on Christ by the sacraments that are generally necessary to salvation. We put on Christ by cooperating with the Holy Spirit who forms within us the virtues, above all charity.
These are gifts of God, provided like the wedding garment given to each guest. We are invited and granted mercy and grace, to be partakers of the inheritance of the saints in light, to be partakers of the divine nature having escaped the corruption that is in the world through lust. (II Pet. 1:4) We are given everything we need so that we come behind in no gift; waiting for the coming of our Lord Jesus Christ. As you are called in Christ, to become saints in Christ, so live in Christ, having been baptized into his death unto sin, and in whom you live unto righteousness.
If you refuse the invitation, or if you come to the feast but refuse the gracious provision of the king, it is your choice to come under wrath, never understanding the heart of one who calls you "friend." Above all, from the cross he has called you "friend." Do not turn from his love, and so place yourself under wrath by your own stubborn willfulness.
Put on the Lord Jesus Christ.