1. Marriage is a civil right granted by the government.
2. Everyone should have the same civil rights under the law, regardless of their sexual orientation.
3. Same-sex marriage hasn't been recognized in every state, so it is not settled.
4. Same-sex marriage has come to symbolize the greater struggle for acceptance and legal equality for LGBT people. It raises the basic question of whether it's OK to treat people differently because of the sexual orientation and whether being gay is wrong/a choice. So, the fight for SSM has advanced acceptance and equality for gay people across the board.
5. The US still has tons of homophobia and mistreatment of gay people so we have a lot of work to do in general to make acceptance of homosexuality a social norm. We've come a lot way in the past 10 years, but there are still anti-gay hate crimes, conversion therapy and bullying of gay kids going on. We can't accept second-class citizen status on any issue or be complacent even when we've had some political success in recent years. As if it's OK to be homophobic or legally discriminated against in some states. It's never OK and we shouldn't have to take it any longer.
I have a reasonable counter here.
1. Marriage and the family was instituted before the concept of human government. Thus goes beyond civil rights. (Look at Genesis 2-4 on this)
2. Those who want to change that are trying to undermine cultural and societal norms that have always existed. Thus the burden of proof to change roughly the whole of human history is on the ones trying to change that incontrovertible fact.
3. The Founders to a man agreed with the Biblical view of marriage and family life and shouldn't we at least consider the wisdom of the founders even if many of you want to cast off the Bible and its role in American jurisprudence.
4. For the courts to undermine the will of the people specifically expressed through their legislatures or through voter referendum to codify traditional marriage as the only acceptable marriage in said state is a stain on the very courts themselves
5. The state's who had bans on SSM who had them overturned by federal courts (yes I'm looking at you too California and Prop 
should have said bans restored and all said "unions" voided from the state records at minimum.
21“Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but only the one who does the will of my Father who is in heaven. 22Many will say to me on that day, ‘Lord, Lord, did we not prophesy in your name and in your name drive out demons and in your name perform many miracles?’ 23Then I will tell them plainly, ‘I never knew you. Away from me, you evildoers!’
1“Do not judge, or you too will be judged. 2For in the same way you judge others, you will be judged, and with the measure you use, it will be measured to you.
3“Why do you look at the speck of sawdust in your brother’s eye and pay no attention to the plank in your own eye? 4How can you say to your brother, ‘Let me take the speck out of your eye,’ when all the time there is a plank in your own eye? 5You hypocrite, first take the plank out of your own eye, and then you will see clearly to remove the speck from your brother’s eye.
Especially pay attention to verse 3, Calvinist.
