The Supreme Court begins hearing oral arguments Tuesday about the consitutionality of state and national laws banning same-sex marriages.

Yet, before the justices took their places at the bench - and even before the planned rally on the steps of the courthouse, an interfaith group met at the Lutheran Church of the Reformation in D.C. to pray for "love and justice."

The prayer meeting was led by Rev. Gary Hall, dean of the National Cathedral in Washington D.C, who is also speaking at the United for Marriage rally at the court. In January, the National Cathredal cast its vote firmly in support of same-sex marriage, when it announced it would begin performing same-sex weddings.

"I honestly didn't realize it was going to be such a big news story," Hall said in a press release. "But the symbolism of this iconic church where the nation gathers in significant moments of our common life standing up for marriage equality was felt far and wide by LGBT people and their allies across the country."

Other religious groups are showing their support for same-sex marriage – many through the Human Rights Campaign's Facebook campaign, which urges supporters to use a red version of their logo as their profile picture, and to change their cover photo to a picture of the Supreme Court.

HRC is also encouraging supporters to wear red today, as Christians for Marriage Equality shared on their Facebook page.

This is the first time the issue of same-sex marriage has come before the Supreme Court, and two cases will be brought to the bench.

Today the Court will hear arguements in Hollingsworth v. Perry, which specifically looks at California's Proposition 8, which bans same-sex marriages in the state. If the court finds the ban unconsitutional, it could over turn it – even though the majority of California voters supported it in 2008.

Later, the Court will hear arguements in United States v. Windsor, which deals with the constiutionality of the 1996 Defense of Marriage Act.

Legal analysts say the Court could rule one of three ways: it could say same-sex marriages are a constiutionally supported right, thus reversing Prop 8 and the constitutions of the 30 states that currently have constiutional amendments banning same-sex marriages.

The Court could also rule that same-sex marriage is not a consitutionally supported right, or that there is no difference between marriage and civil unions.

A decision is expected by the end of June.

Traditional Protestant churches in North America have faced splits over the issue of same-sex marriage which has progressively gained greater acceptance in society.

A poll released by the Public Religion Research Institute on Saturday found that 52 percent of Americans favour the U.S. Government recognizing same-sex marriages, with 42 percent opposed.

The finding from the institute was released just days before the U.S. Supreme Court hears oral arguments in two landmark cases involving marriage equality next week.