Matthew 18:15 If your brother sins against you... looking at the 10 commandments I don't see how a wedding invitation or acceptance is a sin against the recipient. Homosexuality is a sexual sin, along with adultery, and fornication; Every wedding I have ever attended both people getting married are sinners and will in all likelihood sin again. Matthew 22:39 you shall love your neighbor as yourself. 1 Corinthians 6:9 Or do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived: neither the sexually immoral, nor idolaters, nor adulterers, nor men who practice homosexuality, 10 nor thieves, nor the greedy, nor drunkards, nor revilers, nor swindlers will inherit the kingdom of God. 11 And such were some of you. But you were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and by the Spirit of our God. The question outstanding is; Is merely attending a celebration of a homosexual wedding condoning the sin? We must ask ourselves What Would Jesus Do. John 8:7 And as they continued to ask him, he stood up and said to them, “Let him who is without sin among you be the first to throw a stone at her.” 8 And once more he bent down and wrote on the ground.9 But when they heard it, they went away one by one, beginning with the older ones, and Jesus was left alone with the woman standing before him. 10 Jesus stood up and said to her, “Woman, where are they? Has no one condemned you?” 11 She said, “No one, Lord.” And Jesus said, “Neither do I condemn you; go, and from now on sin no more.”