A family-owned Christian bakery, under investigation for refusing to bake a wedding cake for a lesbian couple, has been forced to close its doors after a vicious boycott by militant homosexual activists.

Sweet Cakes By Melissa posted a message on its Facebook page alerting customers that their Gresham, Ore. retail store would be shut down after months of harassment from pro-gay marriage forces.

“Better is a poor man who walks in integrity than a rich man who is crooked in his ways,” read a posting from Proverbs on the bakery’s Facebook page.

“It’s a sad day for Christian business owners and it’s a sad day for the First Amendment,” owner Aaron Klein told me. “The LGBT attacks are the reason we are shutting down the shop. They have killed our business through mob tactics.”

Last January, Aaron and Melissa Klein made national headlines when they refused to bake a wedding cake for a lesbian couple.

Klein tells me he has nothing against homosexuals – but because of their religious faith, the family simply cannot take part in gay wedding events.

“I believe marriage is between a man and a woman,” he said. “I don’t want to help somebody celebrate a commitment to a lifetime of sin.”

The lesbian couple filed a discrimination with the Oregon Bureau of Labor and Industries and told their story to local newspapers and television statements.

Within days, militant homosexuals groups launched protests and boycotts. Klein told me he received messages threatening to kill his family. They hoped his children would die.

The LGBT protestors then turned on other wedding vendors around the community. They threatened to boycott any florists, wedding planners or other vendors that did business with Sweet Cakes By Melissa.

“That tipped the scales,” Klein said. “The LGBT activists inundated them with phone calls and threatened them. They would tell our vendors, ‘If you don’t stop doing business with Sweet Cakes By Melissa, we will shut you down.’”

To make matters worse, the Oregon’s Bureau of Labor and Industries announced last month they had launched a formal discrimination investigation against the Christian family.

Commissioner Brad Avakian told The Oregonian that he was committed to a fair and thorough investigation to determine whether the bakery discriminated against the lesbians.

“Everybody is entitled to their own beliefs, but that doesn’t mean that folks have the right to discriminate,” he told the newspaper. “The goal is to rehabilitate. For those who do violate the law, we want them to learn from that experience and have a good, successful business in Oregon.”

In other words, Christians who live and work in Oregon must follow man’s law instead of God’s law. But in a show of benevolence, the state is willing to rehabilitate and reeducate Christian business owners like the Kleins.

Klein said the closing of their retail store was a small price to pay for standing up for their religious beliefs.

“As a man of faith, I am in good spirits,” he said. “I’m happy to be serving the Lord and standing up for what’s right.”

Klein said what’s happened to Sweet Cakes By Melissa should be a warning to other Christians across the nation.

“This is a fight that’s been coming for a while,” he said. “Be prepared to take a stand. Hopefully, the church will wake up and understand that we are under attack right now.”

Just last month, New Mexico’s Supreme Court ruled that two Christian photographers who declined to photograph a same-sex union violated the state’s Human Rights Act. One justice said the photographers were “compelled by law to compromise the very religious beliefs that inspire their lives.”

Denver baker Jack Phillips is facing possible jail time for refusing to bake a cake for a gay wedding.

The Colorado Attorney General’s office filed a formal complaint against Phillips, the owner of Masterpiece Cake Shop. A hearing before the state’s civil rights commission is set for later this month.

In Indianapolis, a family-owned cookie shop faced a discrimination investigation after they refused to make rainbow cookies for National Coming Out Day.

A T-shirt company in Lexington, Ky. found itself at the center of a Human Rights Commission investigation after they refused to make T-shirts for a local gay rights organization.

Klein said it’s becoming clear that Christians do not have the “right to believe what we believe.”

In other words, gay rights trump religious rights.

Aaron and Melissa Klein tell me they will continue to bake wedding cakes from their home. He’s already taken a full-time job to pay the bills and feed their five children.

Mrs. Klein told television station KPTV her philosophy remains unchanged by recent events.

“The Bible tells us to flee from sin,” she said. “I don’t think making a cake for it helps. I guess in my mind I thought we lived in a lot nicer of a world where everybody tolerated everybody.”

The plight of the Klein family exposes the true nature of the left. Those who preach tolerance and diversity are the least tolerant and the least diverse of all.

Todd Starnes is the host of FOX News & Commentary. You can follow him on Facebook and Twitter.