In June 2009, she was working with a group of Muslim women, picking berries in a field. She was sent to fill a bucket with drinking water. When she returned, the Muslim women would not drink from it. It was impure, they said, having been touched by a Christian.
What Bibi said then is a matter of dispute.
A local police officer later told CNN what Bibi's accusers claimed she said.
"(T)he Quran is fake, and your prophet remained in bed for one month before his death because he had worms in his ears and mouth," the policeman said Bibi is alleged to have said. "He married Khadija just for money and after looting her kicked her out of her house."
Bibi denied it. "I would never even think of blasphemy," she later explained in a television interview.
Immediately after the argument in the field, nothing happened.
However, according to news reports, the Muslim women went to a local cleric and accused Bibi of blasphemy.
CNN reported that Section 295 C of the Pakistani penal code says: "Whoever ... defiles the sacred name of the Holy Prophet Muhammad (peace be upon him) shall be punished with death, or imprisonment for life, and shall also be liable to fine."
For five days after the incident in the field, according to the London Telegraph, Bibi was surrounded by a mob.
"They said she had told them Jesus had been resurrected while Muhammed had died - claims her supporters emphatically deny - and demanded she recant and convert to Islam," the Telegraph reported.
The police took Bibi into custody for her own protection.
"The police station was crowded by the Muslim ulemas (religious scholars)," the Pakistani Minister of Religious Minorities Shahbaz Bhatti, a Catholic, told The Washington Post. "They said, 'If you will not register the case, she will be killed at this spot right now.'"
Blasphemy charges were filed against Bibi. She was imprisoned for a year and a half. Then, in November 2010, she was tried in a local court and, according to the Telegraph, was "convicted on the evidence of two witnesses who were not present in the fields where the exchange is supposed to have taken place."
Asia Bibi's five children and her husband became fugitives in their own country - even though they had committed no crime. Fearing their neighbors, they moved from place to place, sheltered by courageous allies.
"I keep getting phone calls from people with hidden numbers asking where I am and whether they can meet me, but I know what they want," the husband told the Telegraph. "They want us dead."
Others were martyred.
Bhatti, the Catholic minister of religious minorities, investigated the Bibi case and recommended to Pakistani President Asif Ali Zardari, the widower of assassinated former Prime Minister Benazir Bhutto, that Bibi be pardoned. He also recommended Pakistan's blasphemy law be changed.
Salman Taseer, the Muslim governor of the Punjab, backed Bibi's petition for a pardon. "I am going to take this petition to the president, and the president will forgive her," Taseer said, according to The Associated Press.
In January 2010, one of Taseer's bodyguards shot him in the back - and then confessed.
When he entered court the next day, according to National Public Radio, "young lawyers ... showered the assassin with rose petals."
A month after Taseer's assassination, Bhatti told the Christian Post: "I received a call from the Taliban commander and he said, 'If you will bring any changes in the blasphemy law and speak on this issue, then you will be killed. ... I don't believe that bodyguards can save me after the assassination (of Taseer). I believe in the protection from heaven."
In March 2010, assassins gunned Bhatti down in his car.
The BBC then reported that Bhatti had "recorded a statement in December, and asked that it be sent to the BBC in the event of his death."
"I am living for my community, and for suffering people, and I will die to defend their rights," Bhatti said in the statement.
Last week, Secretary of State Hillary Clinton released her department's annual International Religious Freedom Report. It listed eight "Countries of Particular Concern" that had "engaged in or tolerated particularly severe violations of religious freedom."
Pakistan was not one of them.
The report did say that "after initially signaling he was considering pardoning Aasia Bibi's death penalty sentence for alleged blasphemy, President Zardari refrained from doing so."
The State Department said Bibi remains in custody.
President Barack Obama came to office offering a new vision for American diplomacy in the Muslim world. Here is his chance to prove it works.
He should rally the leaders of all the major Muslim nations -- including Turkey, Saudi Arabia and the United Arab Emirates, which enjoy close relations with the United States -- to call on Pakistan to pardon and free Asia Bibi and let her and her family come to America.
He should challenge them openly and boldly to give the whole world an opportunity to see their commitment to tolerance and freedom of conscience.