Bono has called for a Europe of mercy to refugees as U2 played its first concert since the Paris attacks.
The Irish rock stars were among those to cancel high-profile gigs in the French capital following Friday's terrorist attacks, which saw at least 129 killed and hundreds injured.
Guitarist Adam Clayton wore a Stiff Little Fingers T-shirt in tribute to the Northern Ireland outfit which refused to cancel a concert following the carnage.
Bono asked Belfast concertgoers whether they wanted "a Europe with its heart open or its borders closed to mercy".
Footage of a bombed-out Syrian city and refugees walking on railway tracks created a dramatic backdrop to the gig.
U2 played anti-war classic Bloody Sunday as well as material from new album Songs of Innocence.
Bono quoted former South African leader Nelson Mandela's attitude to struggle. "He said it always seems impossible until it is done," he said.
Physicist Stephen Hawking's quote calling for global citizens was also rolled out. The concert finished with the crowd joining in a rendition of One. The U2 frontman also referred to the battle against Aids.
This was the first time U2 had played in Belfast since their 1997 Pop tour.
They performed at a packed SSE Arena, a nostalgic theme focusing on the early years in north Dublin and Bono's courtship with his wife.
They play tomorrow night in Belfast before four nights at Dublin's 3Arena on Monday and Tuesday November 23 and 24 before breaking for a few days to return to the stage on the Friday and Saturday night, November 27 and 28.
A passport from a Syrian man who entered Europe on the refugee trail was reportedly found near one of the Paris bombers. The discovery has already prompted tighter restrictions on the travellers entering parts of Germany.
The bloodiest attack came at the Bataclan theatre, where American rockers Eagles of Death Metal were performing when gunmen stormed the venue.
But Bono urged people to refuse to hate. "We know that love will do a better job," he said.
He paid tribute to the peacemakers of Belfast as a large screen showed the Eiffel Tower, Arc de Triomphe and displayed the message Vive La France.