Vice President Joe Biden has applauded passage of a referendum on same-sex marriage in Ireland, now the first country to legalize such unions through a popular vote.

Voters in mostly Roman Catholic Ireland headed to the polls on Friday. The following day, thousands gathered at Dublin Castle's central square, where returns were being announced live on big-screen televisions. The referendum passed with more than 62% of the vote.

(Related: Irish voters resoundingly approve gay marriage.)

In an op-ed published Thursday, Biden praised the Irish people for taking a “courageous stand for love and family.”

“They recognized the fundamental truth that every person is entitled to dignity and respect, and that there can be no justification for the denigration or persecution of anyone because of who they love or who they are.”

Biden reflected on how the gay rights movement has grown in Ireland and the United States.

“In 22 years, Ireland has gone from a nation where simply being LGBT was against the law to a nation where the people resoundingly stand for equal rights.”

“And here in the United States, in just the past three years we've gone from six states recognizing marriage equality to 37 states, compromising 224 million Americans. It's about love. It's about equality. It's about dignity. It's about our most cherished values. That's what this is about – it's all it's ever been about,” he wrote.

Biden added that it takes “courageous individuals who are willing to step forward, to turn adversity into positive change” and concluded with a quote from Irish poet William Butler Yeats: “Do not wait to strike till the iron is hot, but make it hot by striking.”