Participating in weekly runs with legendary marathon champion Johnny Kelley back in the 1970s was a lot like attending a religious service.

We congregants flocked on Sunday mornings to the house of worship, 415 Pequot Ave. in Mystic, waiting for our spiritual leader to don his vestments – nylon shorts, a T-shirt and Tiger Jayhawk running shoes with holes worn through the sides from Kell’s oversized bunions.

The sermon took place not on the mount but on the run, and you had to hang on Johnny’s shoulder to catch every word.

Here, I guess, the liturgical reference may not apply because Johnny could be hilariously profane, but at least he always was inspirational.

Among the many acolytes at the time was an energetic young man named Ian Fairgrieve, who coined a phrase that Johnny later adopted and I eventually embraced: “Gotta do it!”

This was decades before Nike employed the advertising slogan, “Just do it,” and I’ve long suspected Ian’s oft-repeated imprecation eventually found its way to the ears of a Madison Avenue copywriter.

Anyway, this would be a typical exchange while running:

Kell: “Anybody want to cut through the Pequot Woods?”

Ian: “Gotta do it!”

Chorus: “Gotta do it! Gotta do it!”

Or, having a round at the late-great Jolly Beggar’s café in Mystic:

Kell: “That’s it for me … Well, maybe one more ….”

Ian: “Gotta do it!”

Whenever Johnny and I contemplated an adventure – kayaking in rapids, sailing to Fishers Island and running barefoot on the beach, biking to Misquamicut for body surfing, hiking in the White Mountains, loping along on a 30-mile run on my 30th birthday, jumping into Fishers Island Sound on New Year’s Day, or taking an impromptu road trip for a Muddy Waters concert – we’d look at each other and exclaim, “Gotta do it!”

Kell looked an acted more like a high-spirited kid than a champ, and never talked about his astonishing career – he won the Boston Marathon in 1957, the Pan American Games marathon in 1959 and the Yonkers Marathon, the national championship, from 1956 to 1963. He also ran two U.S. Olympic marathons, at Melbourne in 1956 and Rome in 1960.

Amby Burfoot, who ran on a cross-country team at Fitch High School in Groton that Johnny coached, and then went on to win the Boston Marathon in 1968, calls his mentor the father of long-distance running in the United States.

Amby and I went on a five-mile run earlier this week and talked, of course, about Johnny, and about the big day this Sunday, Sept. 21.

That’s when a statue of Johnny and his beloved dog, Brutus, will be unveiled at a small park near Bank Square in downtown Mystic. Everybody’s invited to the 1 p.m. ceremony; I hope you can make it.

After Johnny died three years ago at age 80, his many friends raised more than enough money to commission the statue, and whatever’s left over will be used for scholarships.

Jim Roy, another former student who took charge of the statue committee, did an amazing job helping preserve Johnny’s legacy.

Jim, Amby and others on the committee talked about how Johnny shunned the spotlight, but we all agreed he would be pleased that the statue isn’t meant to celebrate the man, but rather his joyous spirit.

Johnny taught me, and generations of runners and non-runners alike, the value of carpe diem, seizing the day – or as Ian would say, “Gotta do it!”