Jack, 17, is quite a star student at his local church.
The newly-crowned Model Student of the Year at a neighbourhood school has just completed N levels, topping his class with scores of 3 As, 1 B and 2 Cs. He is 'now influencing friends around me to study'.
And, at a recent service at the Heart of God Church in Paya Lebar, he told the congregation that he recites mathematics formulas, instead of hurling vulgarities, like he used to.
'I would say things like x = (-b + vb2-4ac)/ 2a,' he said. 'As a result, maths is my best subject now!'
But Jack's path to academic success is far from usual.
The polite teen was until last year a gang member.
From the age of 13 to 15, fighting and stealing hand phones was the norm for the youth who sports tattoos over half of his back.
His break from an all-too-predictable future came when he was beaten up by members of his own gang and, upset, dropped by the church he once visited years ago with friends.
This led to him being invited by two mentors from the youth-friendly church to join other teens for a Father's Day meal at Fish and Co.
'They wanted us to know what it's like to have a happy family to spend Father's Day with,' he recalls.
Stories of gangsters-turned-good guys are not uncommon, according to the church of 1,000 youths and 250 adults.
Amid the tense headlines on youth gangs, religion seems to offer some glimmer of hope.
With ex-offenders known to make an easy transition from the brotherhood of gangs to the family of faith, religion offers a glimmer of hope against the grim backdrop of increasing youth gang crime.
Youth specialist Glenn Lim, a former drug addict involved in the gang scene from 16 to 23, points out that organised religion offers a sense of community.
With gangs, as with religion, there is a sense of belonging, acceptance and significance, as well as power, says Mr Lim, who now trains youth pastors at the School of Youth Ministry. He also founded Architects of Life, where former delinquents mentor troubled youths.
Adult mentors and youth clerics are now a growing presence in temples, mosques and churches.
And it's clear that these committed adults, who spend time with youth, sometimes online, make an impact.
One Muslim instructor does this innocuously enough by visiting his students' Facebook pages - when they occasionally use vulgarities, he leaves a comment on some other subject, just to show his presence. He says it works.
At the Singapore Buddhist Mission youth group, Venerable Bodhi, 40, regularly drops in to lead discussions. She unpacks complex Buddhist concepts through folksy allegories and laughs merrily at the youth circle’s antics. It’s evident that she enjoys their company, even as she guides their conversation with grace and firmness.
Among the Taoists, Hindus, Sikhs and Bahá'í, dynamic young adults, all not much older than their teenage charges, too give of their time, providing insight and friendship.
They bridge the generations, and build young faith. And they offer a quiet bulwark against the demons of cynicism and violence against which youth battle.