She believes she heard the voice of God loud and clear on the morning of September 11, 2001 at the 81st floor of the World Trade Center when the terrorists struck with their hijacked planes.

Speaking to CBN News on the occasion of the 15th anniversary of the deadliest terrorist attack on America, Jean Potter said she was there working at the 81st floor of the 110-storey North Tower when the first plane hit the skyscraper between floors 93 and 99. According to authorities, the aircraft entered the tower intact and plowed to the building's core before exploding.

"All of a sudden, this massive explosion rocked the building, and we literally swayed from side to side," Jean told CBN News.

In the midst of chaos, she said she heard God's voice telling her, "This is not your time. We are with you. Your brother is with you." Jean lost her brother in 1999.

Jean and her fellow workers quickly climbed down the staircase as flames engulfed the floor they were standing on.

"My heart was palpitating a mile a minute as I was going down the staircase," she recounted.

Then God's voice again spoke to her, saying, "You and Dan [her husband] will be blessed with a beautiful life. You will go north."

"And I saw like green trees. This is all while this is happening, and I'm in a very nervous state, but the messages were coming in," Jean said.

She said she realised that God was with her all the time, reassuring her and prodding her to keep moving down the staircase.

Jean's husband Dan happened to be a firefighter but was on nearby Staten Island when the terrorists struck. Upon hearing the dire news, he raced to Manhattan to make sure Jean was safe. At that time he didn't know yet that she made it out of the North Tower before it collapsed.

Dan arrived at ground zero and saw the South Tower collapsed and later, the North Tower.

Debris and concrete rained down on Dan, but he said God kept him alive, and "the big hit" never came.

Covered in ash, Dan eventually reunited with his wife—a moment both of them could never forget.

Jean asked him, "Where were you?"

"He said, 'You don't want to know,' and we hugged. It was just unbelievable," she recalled. "We are so grateful for what Jesus has done in our life."

Jean and Dan's amazing story of survival is chronicled in the book, "By the Grace of God, A 9/11 Survivor's Story of Love, Hope, and Healing."