CHICAGO — Standing in a security line at O’Hare International Airport seven years ago, the Rev. Bobby Gruenewald wished he had a Bible in his pocket to pass the time. Then the tech-savvy pastor raised in central Illinois had a thought: Wouldn’t it be grand if anyone could have their favorite version of the Bible within reach anywhere at any time?

“Could we be at one of these moments in history where technology, if we leverage it correctly, could transform how we engage in the Bible?” Gruenewald, 37, recalls thinking that day. “Drawing from the story of the printing press, for centuries, that really changed our access to the Bible. It’s probably something today we easily take for granted, but it came through invention.”

By the time he reached the gate to board his flight, Gruenewald, now the innovation pastor of an Oklahoma-based megachurch called LifeChurch.tv, had already registered a Web domain name, youversion.com, and hatched a plan that would lead to the world’s most popular Bible app.

That app, YouVersion, recently exceeded 100 million downloads and offers the holy book in 617 versions and 377 languages.

Represented by the simple icon of a Bible with a bookmark, the app offers audio versions for listeners, navigation tools to look up passages, social media capability to share verses on Facebook and Twitter, and private or public platforms to store or share notes. The app is free and generates no revenue for the church. It simply aims to fulfill the Christian mission of spreading God’s word, Gruenewald said.

YouVersion didn’t see instant success, he said. Its full potential didn’t emerge until mobile devices began to catch on. In fact, the church was on the brink of shutting down the endeavor when Apple introduced its App Store for the iPhone in 2008.