By his students. That’s how I know Imam Fethullah Gülen, may his memory be a blessing.

Rooted in Turkish Sunni Islam, Mr. Gülen’s teachings, faith, and way of life focused on education, achievement, charity, and positive engagement with people of other faiths. The movement he inspired—Hizmet (service, in Turkish)—focused the energies of hundreds of thousands of Turks and others to apply their acumen, resources, and business and professional networks, to build robust civil-society organizations.

Mr. Gülen modeled for his students worldwide the values of graciousness, generosity, and fidelity to principles.

My nearly 20-year relationship with Hizmet began through the Niagara Foundation in Chicago, whose representatives reached out to the Jewish community after their arrival. I was privileged to work with them on interfaith issues, outreach, and dialogue for much of my career as a communications executive at Chicago’s Jewish Federation.

At first, Mr. Gülen and Hizmet were mysteries to my colleagues and me. We all wanted to know: who are these people and what do they want? I was particularly curious due to having some background in Turkish language and culture.

The answers emerged, more implicitly than overtly, throughout our long relationship. If I had to sum up Hizmet’s message in one phrase, it is: “Be the change you want to see.”

Both our peoples, Turks and Muslims, and Jews and Israelis, have experienced triumphs and endured calamities, which can make people bitter. Persecutions of Hizmet in Turkey began in 2013 and exploded in a violent purge in the summer of 2016. The Turkish government under President Erdoğan arrested, imprisoned, tortured, impoverished, and exiled thousands on the debunked pretext that Mr. Gülen was behind an alleged coup attempt (likely a false-flag operation).

Despite the depredations they continue to suffer, the students of Mr. Gülen I know are not bitter. Indeed, they continue to plant the seeds of respect, human kindness, learning, charity, and peace, for those are the pillars of their faith.

Through them I have come to know their teacher, their beloved Hocaefendi, who I was honored to meet a few years back.

May the day come when the good people of Hizmet know no fear in their beloved homeland. May the day come quickly when the spirit and teachings of Mr. Gülen help those of good conscience and good faith make the change all peace-loving people want to see.