Greed is not good. Ari Schonbrun, once a high-powered financial services executive, came to realize that after Sept. 11, 2001, when he survived the attack on Tower One of the World Trade Center (WTC) in New York.

He walked away from the terrorist attack “without a scratch” and, three years ago, walked away from Wall Street altogether. He now speaks full time about the lessons he learned.

On Sept. 23, he captivated an audience at Chabad of the Town in Montreal, talking about how he used to be driven to make more and more money, but since 9/11 has been devoted to his family and to serving God.

“The hand of God is the only reason I’m standing here today,” he said.

As Rabbi Moshe Krasnanski, the director of Chabad of the Town, noted, that day was the 18th anniversary of 9/11 – 23 Elul on the Hebrew calendar.

Schonbrun was the chief administrative officer of Cantor Fitzgerald, whose corporate headquarters occupied the 101st to 105th floors of the first tower to be hit. All 658 employees in their offices that morning were killed.

Schonbrun was one of only four employees in the building who survived. The other three suffered serious burns, and one died afterward. He described in vivid detail, and with surprising humour, what happened to him that day.

“There were multimillionaires who were at their offices at 6:30 a.m. Their motto was greed. It was all about the money – the bigger house, better car, next promotion – that was all that mattered. And I was guilty of the same thing,” he said.

Schonbrun, who had four children under 15, said he wasn’t there for their school plays or games. “It was always, ‘daddy’s gotta work.’ ” he said. “Now I’m wherever the kids, and the grandchildren, want me – everything else is secondary.”

He outlined a series of circumstances that spared him on 9/11.

The first was his eight-year-old son forgetting to bring home a book order from school. On that fateful morning, Schonbrun reluctantly heeded his busy wife’s appeal to fill out the overdue form before he left for the office.

That 20-minute delay, which left him “seething,” probably saved his life, as Schonbrun did not reach his desk at his usual time.

The WTC’s ground elevators did not reach the uppermost floors. Passengers had to disembark at the 78th floor and take other elevators.

While he was waiting for that second elevator, the first airplane struck the tower. Schonbrun thought it was a bomb. A co-worker, Virginia DiChiara, who had just gotten on an elevator going up, jumped through the fire, sustaining third-degree burns.

Through the smoke and chaos, he was somehow able to find the door to the stairwell and guided DiChiara, who was in excruciating pain, down.

At the 75th floor, Schonbrun received a call on his cellphone from his wife, which was “a miracle, because we never got reception in the WTC,” he said.

She said something about a plane, but he abruptly cut her off, telling her it was not a good time to talk.

Finally at the first floor, Schonbrun decided to continue to the underground garage, but someone opened the door and warned them that they could not get out that way. “He saved our lives; no one in the garage ever got out,” Schonbrun said.

Back in the lobby, Schonbrun, still with a weakening DiChiara, was told by firefighters to take the long way out. “The West Street was where people jumping (landed). I thank God every day I did not see that live,” he said.

By then, the second tower was on fire and confusion reigned on the streets. They found an ambulance and DiChiara pleaded with Schonbrun to come with her, which he initially refused, but changed his mind.

“If she had not insisted, I would have been at the base of that building when it collapsed and be dead,” he said.

At 12:45 p.m., Schonbrun tried to contact his wife, but cellphones were not working and the payphones were jammed.

A stranger on the street invited Schonbrun into his tiny apartment to use his landline. Reaching his parents who lived in Israel was another story, as no international lines were open that day, Schonbrun said.

When he made it to his brother’s uptown office, Schonbrun “cried in his arms for a solid five minutes. I’d been strong the whole day, finally I could lean on someone.”

Schonbrun was an observant Jew before 9/11, but his faith only strengthened by the incident.

“It’s no coincidence 9/11 was exactly a week before Rosh Hashanah. God is telling us to wake up, do something different,” he said. “Why are we on earth? To serve God. For us, it is simple, because God gave us the Torah, it’s the blueprint.”

That doesn’t mean keeping all 613 commandments, he said. “Do one mitzvah a day and own it. Start doing it to the letter of the law.… See the effect on you, and those around you. God whispers to our hearts and minds, but we are so busy running through life to listen.”

The couple had a fifth, unexpected child two years after 9/11. A Kabbalist told them the boy had the soul of another that was lost in a much earlier pregnancy that did not go to term.

This is yet another reason he was saved, according to Schonbrun.