Ours is an unlikely friendship. One of us (Gonen ben Itzhak) is an Israeli, the son of a retired Israel Defense Forces (IDF) general who was in charge of defeating the first intifada some 20 years ago. One of us (Mosab Hassan Yousef) is a Palestinian, the son of a founder of Hamas whose father was one of the leaders of that intifada. The Palestinians' goal for the intifada was to elevate their cause. Israel sought to keep violence down and protect its citizens. Today we are sacrificing everything -- possibly even our lives -- to build a bridge of peace between our peoples.

As detailed in the book "Son of Hamas," published this year, we became partners in the fight against terrorism; Mosab became an undercover agent for the Shin Bet, Israel's security service; Gonen became his Shin Bet handler. In the nine years we worked together, the two of us, once sworn enemies, embraced mutual recognition and rejected the mind-set of revenge.

All the efforts of Hamas and the Palestine Liberation Organization failed to achieve the goals of the intifada. All the efforts of the IDF failed to stop the hate that fueled the intifada.

Mosab observed firsthand the craziness of the cycle of violence. Mosab began to question who his real enemies were: the Hamas leaders who tortured their fellow Palestinian prisoners, or the Shin Bet, who arrested and imprisoned him. Over the 16 months that Mosab was in prison, the answer became clear, and this persuaded Mosab to go undercover for the Shin Bet. Gonen, whose code name was "Captain Loai," became Mosab's handler. Mosab's reports led to the arrests of several high-ranking Palestinian figures. As we worked together to prevent the deaths of hundreds of Israelis and Palestinians, the two of us became friends.

We believe that friendships like ours are key to eliminating hate and promoting the liberty that both our peoples so desperately desire.

Mosab converted to Christianity in 2005 and moved to California in 2007. America has a vision of a world where liberty reigns. When Mosab brought terrorists to justice while working undercover for the Shin Bet, he was American at heart, fighting for liberty and justice.

Mosab has lived in this country for more than two years. We were shocked when, in 2009, the Department of Homeland Security opposed his request for political asylum, all the more so when it threatened to deport Mosab in the name of protecting American security. If this decision is upheld, it will signal to the world that America does not stand by those who sacrifice to oppose terrorism. If America wants liberty to prevail in all places, it must not abandon those who share the ideals of freedom.

Gathering human intelligence in the war against terrorism will become impossible if the United States does not protect those who risk their lives on behalf of American values.

Mosab was born a son of Hamas, but he rejected his violent destiny and found the strength to choose a different path. But having left revenge behind, he faces possible deportation as payback for embracing the ideal of loving his enemy.

When an immigration judge in California decides about Mosab's future on Wednesday, the ramifications will be much greater than whether he is sent back to certain death anywhere in the Middle East. It is a decision about the future of liberty and about the best path to peace.

Whatever happens in San Diego, we hope that our story can be a bridge to peace. Peace is a state of mind and heart before it is a political reality. Our friendship is proof that hating hearts can change -- and that changed hearts are the only hope for liberty.