Prince Charles has called for an end to the "pervasive horror of knife crime" in an Easter message.
The Prince of Wales says offenders must be punished, but forgiveness has an "extraordinary power" to change them.
It comes as concern grows over youth-related violence, with campaigners calling it a "national emergency".
Prince Charles says he and Prince Harry brought together some of those affected by knife crime.
Although listening to the victims and bereaved filled them with "immense sadness", their determination to find solutions to knife crime was an "example of the light shining in the darkness", Prince Charles writes.
The prince speaks about Gee Walker, whose son, Anthony Walker, was beaten to death with an ice axe in a racist attack in 2005.
Mrs Walker offered forgiveness to Anthony's murderers that was "inspired by the Easter story", says Prince Charles.
"Of course those who commit such brutal deeds need to face up to their crimes through being brought to justice," he writes.
"However, very often it is not the punishment that brings them to their senses and changes them, but rather the extraordinary power of the forgiveness from those they have hurt."
Bereaved parents and anti knife-crime campaigners shut down Westminster Bridge on Wednesday in protest at the government's response to violent crime.
One of the organisers of the demonstration, Lucy Martindale, whose cousin was fatally stabbed, said the government held a Cobra meeting "if there is a terrorist attack and one person is killed".
She continued: "Several people daily are being killed on our streets, why is this not being treated as the national emergency that it is?"
There were 39,818 knife crime offences in the 12 months ending September 2018 - the highest number since comparable data started being compiled.
Thirty-six homicide investigations have been launched in London since the start of the year, including 23 stabbings.
In March the government pledged an extra £100m for police in the areas worst affected by knife violence.
It came after Metropolitan Police Commissioner Cressida Dick said there was "obviously" a link between violent crime and falling police numbers, but Prime Minister Theresa May said there was "no direct correlation".
Victims in 2019
Motives and circumstances behind killings have varied - as have the age and gender of the victims.
Home Secretary Sajid Javid said on Wednesday that he had implemented "a number of approaches" to reduce serious violence.