First, let’s define sin. Sin is anything that creates a barrier between man and God. Violating God’s laws and commandments prevents one from enjoying a healthy relationship with God. Since no man or woman is capable of keeping all of God’s commandments all are sinners. So let’s look at marriage.
Marriage, the intimate relationship between a man and a woman, was established by God. Genesis 2:18-25. Marriage was established for procreation between a man and a woman. Therefore, the term “gay marriage” is a misuse of the word “marriage” as ordained by God the Creator. God’s idea for marriage was to provide a family unit as the basic building block for a fair and just and loving society. True biblical marriage creates a loving environment in which to raise children so that together the family could enjoy God’s creation and ‘fill the earth’ with a people who would come to know, love and honor their Creator.
Any other arrangements or partnership type of intimacy are opposed to God’s standard for marriage. A gay relationship, therefore, breaks God’s laws and like adultery, must be classified as sin. But, the good news is that God is merciful and will forgive sin if a sinner repents–that is turns away from his or her sinful behavior, confesses that sin to God and allows the Holy Spirit to guide him or her away from the sinful behavior. God is faithful to restore His relationship with faithful repentant sinners. God also reminds us “all have sinned and fall short of the glory of God!” (Romans 3:23)
If you would like to learn about how to deal with any sin, including gay marriage, we encourage you to read our post on How to Become a Christian the first step in allowing God to show his grace in forgiving your sin.