A number of same-sex marriage supporters gathered on the steps Los Angeles City Hall Sunday for a 6:30 p.m. rally.
Shirley Jensen attended the rally with her son, whose long-time partner died several years ago. Jensen herself recently became widowed.
"When my husband passed away, I was afforded many legal options that cost me nothing," said Jensen. "Not for my son. Nothing. And it's time, it's past time, that we all live equally."
Meanwhile, marriage equality supporters around the nation have been rallying in every state this weekend.
"Sometimes it takes time for the legalities to catch up," said Jane Wishon with Marriage Equality USA. "But I really can't understand why the Supreme Court would allow Prop 8 to remain in place, especially since now a majority of Californians do support same-sex marriage."
Supporters of Prop 8 are fighting to uphold the ban. They say the Supreme Court should not override the democratic process by imposing a decision.
"This is a huge policy dispute," said Dr. John Eastman, chairman of the National Organization for Marriage. "Maybe redefining marriage will have societal benefits, maybe it won't. But in our country, basic policy judgments like that are supposed to be made by the people. And the people of California have spoken."
The battle for same-sex marriage has gone on in the state for years. Burbank couple Paul Katami and Jeff Zarillo, along with couple Kris Perry and Sandy Stier of Berkeley, Calif., are the plaintiffs in the Prop 8 case. In 2008, voters passed Prop 8 preventing the legality of same-sex marriage after the State Supreme Court ruled it legal. The Supreme Court hearings for Prop 8 will happen Tuesday.
The second case, to be heard Wednesday, involves the Defense of Marriage Act, which defines marriage as being between a man and a woman and prevents same-sex couples who are legally married from receiving a range of federal tax, pension and other benefits otherwise available to straight, married couples.
The Supreme Court's decision is expected by the end of June.
The Associated Press contributed to this report.