The agony of Asia Bibi, a 54-year-old Roman Catholic and mother of five, shows there is something rotten in her country, Pakistan — and in the broader world of Islam.

She was arrested for blasphemy in 2009 after Muslim co-workers on a destitute farm denounced her for merely drinking from the same cup and, during the subsequent quarrel, for “insulting Prophet Muhammad” — a charge Ms. Bibi always denied. Yet she was convicted in 2010 and spent the next eight years in solitary confinement, on death row.

Luckily, Pakistan’s Supreme Court last month saved her from execution, clearing her of the charges and also setting her free. But Pakistan’s militant Islamists, especially those in the notorious Tehreek-e-Labbaik religious party, which is obsessed with punishing blasphemers, were enraged. They forced the government of Prime Minister Imran Khan to accept a court petition to reverse the case and bar Ms. Bibi from leaving the country. She and her family, fearing vigilante violence, went into hiding.

I am hoping that the traumatized family will be able to leave Pakistan safely, to find asylum in some free nation. As a Muslim, I feel ashamed of the cruelty they have suffered at the hands of people who act in the name of my faith.

Of course, in this story there are righteous Muslims to be proud of as well. They include the Supreme Court judges, whose prudent decision that saved Ms. Bibi noted the Prophet Muhammad’s tolerance for Christians. They include Punjabi politician Salman Taser, who stood up for Ms. Bibi in 2011, only to be assassinated for that by his own bodyguard. They include three British imams, who recently joined the campaign to grant asylum to Ms. Bibi in Britain.

In other words, the militant Islamists who want to kill all blasphemers, real or perceived, do not define Islam. But they do define a fanatic, ferocious, dangerous strain within Islam.

This strain has led to various attacks on freedom of expression, the bedrock of civilization, over the past three decades. The first one was the Iranian Ayatollah Ruhollah Khomeini’s infamous 1989 “death fatwa” calling for the execution of the author Salman Rushdie for his irreverent novel, “The Satanic Verses.” Then came the violent reactions to cartoons of the Prophet Muhammad published by the Danish newspaper Jyllands-Posten in 2005. Terrorist attacks on the French satirical magazine Charlie Hebdo followed. And among nations like Pakistan, Iran, Sudan and Saudi Arabia, Ms. Bibi is only one of the many victims of blasphemy laws.

Muslims who support such violent or oppressive responses to blasphemy are missing two important points. One is that it is them, not the blasphemers, who are defaming Islam, by presenting it as an immature tradition that has little room for civilized discourse. The second point is that their zealotry is not as religiously grounded as they think.

To see this, one must look at the Quran — the most fundamental and only undisputed source of Islam. Most notably, throughout all of its 6,236 verses, it never tells Muslims to silence blasphemy with force. It tells them only to respond with dignity.

This appears in the Quranic verses that addressed the tensions between the earliest Muslims and other communities nearby. “You are sure to hear much that is hurtful from those who were given the Scripture before you and from those who associate others with God,” one such verse tells Muslims, only to add, “If you are steadfast and mindful of God, that is the best course.” [3:186]

Another Quranic verse holds up as model Muslims “those who walk humbly on the earth, and who, when the foolish address them, reply, ‘Peace.’” [25:63] Yet another verse addresses the issue of mockery, telling Muslims that when they hear people who ridicule “God’s revelations,” they should just “not sit with them.” [4:140]

However, as Islamic jurisprudence developed over the centuries, much was added to the spirit of the Quran, based often on dubious reports about the words and deeds of the prophet. Blasphemy, in particular sabb al-rasul, or “insulting the prophet,” gradually became a capital crime — but only with objections from prominent jurists like Abu Hanifa, the eighth-century founder of one of the four main Sunni schools. A bigger sin than insulting the prophet is disbelief in God, he reasoned, but Islam decrees no punishment for that.

Today, Pakistan’s liberals, most of whom are faithful Muslims, are referring to such sources in the Islamic tradition to argue against blasphemy laws. They are right. Those laws should be abandoned — in Pakistan and elsewhere.

At the same time, Muslim opinion leaders should help their societies understand that these laws serve not the honor of Islam, but much more mundane interests — for example, persecuting non-Muslim minorities out of greed or jealousy, or silencing Muslims themselves who criticize and challenge the powers that be.

And all Muslims of good faith should stand up more forcefully for people like Asia Bibi, who is falsely accused of blasphemy. Also, they should tolerate those who really do blaspheme and at most “not sit with them,” as the Quran counsels.

They should walk away, saying, “Peace.”