Jessica Rinaldi / Reuters

New England Patriots quarterback Tom Brady wears a decal on his helmet Sunday, Dec. 16, 2012, in tribute to the victims at Sandy Hook Elementary School in Newtown, Conn.

Updated at 8:26 p.m. ET: Americans came together in the thousands Sunday to honor the memories of the 26 victims of the shootings at a Connecticut elementary school.

This Sunday was Gaudete Sunday, the Advent observance of joy and celebration, but in churches and cathedrals across the country, the message was one of reassurance and comfort for the distressed and the afflicted.

Hundreds of people signed a book of condolences and prayed special prayers Sunday morning at Our Lady of the Cross Parish in Holyoke, Mass.

"I lost a little child once, just a matter of days old, and that's still with me although it's 50 years later," Paula Brunault of Holyoke told NBC station WWLP of Springfield, Mass.

"I just know that prayers surround the people, really and truly. It's the best thing we can do for them," she said.

The Rev. Scott Kubinski, pastor of Christ the Redeemer Parish in the Elmira, N.Y., area, denied that the shootings were the will of God. Instead, he told parishioners at St. Casimir's Catholic Church, it was the fruit of the free will that God allows people to have, NBC station WETM of Elmira reported.

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"God isn't happy about it, but God is with us through it all, giving us strength," he said. "That's why people do turn to faith in times of sadness and why they turn to prayer."

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More than 150 chaplains of the Law Enforcement Chaplaincy of Sacramento, Calif., dressed in full police uniform Sunday and visited churches, restaurants and shopping malls to offer hope.

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At Bayside Church, an Evangelical Covenant megachurch in Roseville, Calif., Senior Chaplain Mindi Russell told thousands of families who packed inside to pray for the victims and families of Friday's massacre.

Russell said it was understandable that children were asking why the shooting happened and why so many people were killed. 

As families hugged one another and prayed for the violence to end, Russell reassured the congregation that while there are bad people in the world, there are many more good people, NBC station KCRA of Sacramento reported.

NFL teams also honored the shooting victims, lowering flags to half-staff  and observing a moment of silence before all of Sunday's games. Some teams brought young children onto the field, and players — many of them visibly moved — stood hand in hand with them.

The New England Patriots — whose owner, Robert Kraft, also owns a box company that has a factory less than a mile from Sandy Hook Elementary School — were wearing black-ribbon logos on their helmets for Sunday night's game against the San Francisco 49ers. 

The Patriots also planned to fire 26 white flares — one for each of the victims — at Gillette Stadium in Foxborough, Mass.

The New York Giants wore decals bearing the letters SHES — standing for Sandy Hook Elementary School — on their helmets Sunday for their game in Atlanta against the Falcons. Coach Tom Coughlin told NFL.com that his team had been "very, very much affected" by the shootings.

The New York Jets were to wear the same decal Monday night for their game against the Tennessee Titans.

More content from NBCNews.com:

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• Mom of suspected school shooter was avid gun enthusiast, friend says
• Newtown mourns: Candlelight vigils, Beanie Babies and a lot of tears
• Victims: Daring principal, fun-loving teacher, 6-year-old twin brother
• Lives saved by teachers, custodian and even kids

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