Q. As a Christian, should I attend a same-sex union?
Your question is an important one, and many Christians have faced and will face the issue of attending a same-sex union. Let’s try to think through this issue from s biblical perspective.
First, Jesus did associate with sinners, when the so-called “righteous” folks objected (Matthew 9:9-13; 11:19; Luke 7:36-50; 15:1-10; 19:1-10).
In all these interactions with “sinners” Jesus never participated in their sin, He never approved of their sin (“Go, and sin no more” – John 8:11), and His goal was to save these sinners. Sinners were drawn to Jesus, not because they felt He approved of their sin, but because they saw Him as a Savior, even for them.
Second, Paul warns about the misapplication of his instruction not to associate with immoral people:
9 I wrote you in my letter not to associate with immoral people; 10 I did not at all mean with the immoral people of this world, or with the covetous and swindlers, or with idolaters, for then you would have to go out of the world. 11 But actually, I wrote to you not to associate with any so-called brother if he is an immoral person, or covetous, or an idolater, or a reviler, or a drunkard, or a swindler—not even to eat with such a one. 12 For what have I to do with judging outsiders? Do you not judge those who are within the church? 13 But those who are outside, God judges. REMOVE THE WICKED MAN FROM AMONG YOURSELVES (1 Corinthians 5:9-13).
Paul is not nearly as much a separatist when it comes to the unsaved as he is toward those who profess to know and follow Christ.
Third, we are instructed not to associate/partner with those in spiritual ministry with those who are not believers:
14 Do not be bound together with unbelievers; for what partnership have righteousness and lawlessness, or what fellowship has light with darkness? 15 Or what harmony has Christ with Belial, or what has a believer in common with an unbeliever? 16 Or what agreement has the temple of God with idols? For we are the temple of the living God; just as God said,
“I WILL DWELL IN THEM AND WALK AMONG THEM;
AND I WILL BE THEIR GOD, AND THEY SHALL BE MY PEOPLE.
17 “Therefore, COME OUT FROM THEIR MIDST AND BE SEPARATE,” says the Lord.
“AND DO NOT TOUCH WHAT IS UNCLEAN
And I will welcome you.
18 “And I will be a father to you,
And you shall be sons and daughters to Me,”
Says the Lord Almighty (2 Corinthians 6:14-18).
Attendance of a same-sex union ceremony is almost universally understood as an acceptance and endorsement of that union. It indicates your approval of the union. It also, in some way associates you with the church and/or individual performing the ceremony. You as a Christian are, in some manner, partnering with a person or persons performing the ceremony and participating in a ceremony that is plainly unbiblical.
Here is an apparently unrelated text that may have some measure of application to the question at hand:
13 Therefore let one who speaks in a tongue pray that he may interpret. 14 For if I pray in a tongue, my spirit prays, but my mind is unfruitful. 15 What is the outcome then? I will pray with the spirit and I will pray with the mind also; I will sing with the spirit and I will sing with the mind also. 16 Otherwise if you bless in the spirit only, how will the one who fills the place of the ungifted say the “Amen” at your giving of thanks, since he does not know what you are saying? (1 Corinthians 14:13-16, emphasis mine)
Paul is arguing that it would be improper for someone in church to say “Amen” to words spoken in tongues but not interpreted, and thus not understood. You can only say “Amen” to what you understand and agree with. In effect, attending a same-sex union is your way of saying “Amen” to all that is taking place, and you do know what it means.
Fourth, our actions need to reflect love for God and for our neighbor, but what form should our love take?
9 Let love be without hypocrisy. Abhor what is evil; cling to what is good (Romans 12:9).
This text is huge in terms of its implications. First, real love does not give approval to what is evil, but it clings to what is good. Appearing to approve of evil, when you really don’t approve, is hypocrisy, and this text tells us that true love cannot be hypocritical. Those who know you are a Christian, and disapprove of same-sex marriage, will very quickly conclude that your presence at a same-sex union ceremony is hypocritical. Your actions don’t conform to your profession. Jesus had very strong words of rebuke for the scribes and Pharisees because they were hypocrites.
Woe to those who call evil good, and good evil; Who substitute darkness for light and light for darkness; Who substitute bitter for sweet and sweet for bitter! (Isaiah 5:20)
12 Are You not from everlasting, O LORD, my God, my Holy One? We will not die. You, O LORD, have appointed them to judge; And You, O Rock, have established them to correct. 13 Your eyes are too pure to approve evil, And You can not look on wickedness with favor. Why do You look with favor On those who deal treacherously? Why are You silent when the wicked swallow up Those more righteous than they? (Habakkuk 1:12-13, emphasis mine).
42 Nevertheless many even of the rulers believed in Him, but because of the Pharisees they were not confessing Him, for fear that they would be put out of the synagogue; 43 for they loved the approval of men rather than the approval of God (John 12:42-43).
24 Therefore God gave them over in the lusts of their hearts to impurity, so that their bodies would be dishonored among them. 25 For they exchanged the truth of God for a lie, and worshiped and served the creature rather than the Creator, who is blessed forever. Amen. 26 For this reason God gave them over to degrading passions; for their women exchanged the natural function for that which is unnatural, 27 and in the same way also the men abandoned the natural function of the woman and burned in their desire toward one another, men with men committing indecent acts and receiving in their own persons the due penalty of their error. 28 And just as they did not see fit to acknowledge God any longer, God gave them over to a depraved mind, to do those things which are not proper, 29 being filled with all unrighteousness, wickedness, greed, evil; full of envy, murder, strife, deceit, malice; they aregossips, 30 slanderers, haters of God, insolent, arrogant, boastful, inventors of evil, disobedient to parents, 31 without understanding, untrustworthy, unloving, unmerciful; 32 and although they know the ordinance of God, that those who practice such things are worthy of death, they not only do the same, but also give hearty approval to those who practice them (Romans 1:24-32).
22 The faith which you have, have as your own conviction before God. Happy is he who does not condemn himself in what he approves. 23 But he who doubts is condemned if he eats, because his eating is not from faith; and whatever is not from faith is sin (Romans 14:22-23).
It may be theoretically possible for a Christian to make his or her disapproval known, and attend as one who disapproves of what is taking place, but I doubt very much that the two same-sex persons will be delighted to see them.
My inclination (and for this I have no direct biblical command) is to speak to these folks personally, or write a note, explaining that you love them and thus you cannot give approval to what you know is going to be detrimental for them. Explain that while you will not be attending the ceremony, you do love them and will happily associate with them in another context.
I hope this proves helpful.