Some people say Jesus never spoke on the issue of gay marriage. However, I believe Jesus did speak on the subject indirectly if not directly. Let us read Matt. 19:3-9:
"The Pharisees also came to Him, testing Him, and saying to Him, 'Is it lawful for a man to divorce his wife for just any reason?' And He answered and said to them, 'Have you not read that He who made them at the beginning MADE THEM MALE AND FEMALE, and said, FOR THIS REASON A MAN SHALL LEAVE HIS FATHER AND MOTHER AND BE JOINED TO HIS WIFE, AND THE TWO SHALL BECOME ONE FLESH? So then, they are no longer two but one flesh. Therefore what God has joined together, let not man separate.' They said to Him, 'Why then did Moses command to give a certificate of divorce, and to put her away?' He said to them, 'Moses, because of the hardness of your hearts, permitted you to divorce your wives, but from the beginning it was not so. And I say to you, whoever divorces his wife, except for sexual immorality, and marries another, commits adultery; and whoever marries her who is divorced commits adultery.'" (NKJV)
There are some significant facts in this short exchange that need to be brought out.
(1) We learn from Jesus that God made mankind male and female and that for a purpose, the purpose of a joining together to become one flesh. Now think about that. If the purpose of making mankind male and female was so they could become one flesh (obviously for godly purposes) then if a man mates with another man has he not violated God's purpose for making him a man? If not, why not? God did not make man to become one flesh with another man.
(2) The wife in this marriage scenario was a female. Jesus speaks of the wife and makes it clear the wife is a "her" (see verse 9). Jesus and the Pharisees were agreed on that. The marriage involved a male and a female. I do not know what a couple in a homosexual relationship will call their partner if gay marriage is allowed but I know it cannot be "wife" and be the truth. If the relationship sours over time and there is a divorce what will be divorced? It can't be a wife. Can you have a marriage without a wife? If so where in scripture do you find such a marriage? I have never read of one in scripture and neither have you and Jesus never knew of any either.
(3) We learn what God joined together was a man and a woman, not a man and a man. Does God join together a man and a man? If so Jesus knew nothing about it. If so find the scripture that shows it but I will tell you before you begin it cannot be done. If God does the joining together of a male and female in a marriage and the Bible not once indicates anything other than male and female then who does the joining together of male and male? Is it God or man? This is an important point for the text says God does the joining together. Is God under obligation to accept man's invention, one that opposes directly his purpose for making man male and female?