A Mancunian whose message of solidarity with a local mosque after the Christchurch massacre went viral has said the overwhelming response shows “the power of choosing friendship over fear”.

Andrew Graystone from Levenshulme stood outside the Madina mosque on Friday after hearing about the shooting at two mosques in New Zealand that left 49 people dead.

He held a cardboard sign with a handwritten message: “You are my friends. I will keep watch while you pray.”

Graystone said he was motivated to support the Muslim community after the terrorist attack on Friday morning. “I thought, what would it feel like as a Muslim going to prayers today? I would feel a mixture of enmity and even fear.”

At a time when countries around the world are on high alert in case of further Islamophobic attacks, Graystone decided he wanted to ensure that people attending the local mosque felt safe. “I picked up a card, wrote my message, went down to my local mosque at Barlow Road and stood outside.”

He greeted arriving worshippers with “salaam” or peace. Many people, he said, were suspicious at first. “They thought I was a protester, but when they saw what was written on the board, people warmed to me.”

Graystone stood outside during Friday prayers, unaware that the imam of the mosque had commended him during the service. “When people came out, I was surrounded by hundreds of people. People were thanking me, blessing me. Some people said their faith in humanity was restored.”

Images of Graystone holding his sign were widely shared on social media, with many commending his act of solidarity.

“I have received around 100,000 messages in the last 24 hours, and hardly any negative messages. That shows the power of choosing friendship over fear.”

Graystone belongs to a church, and says there is a network of local faith organisations whichwork together to maintain social cohesion. He says there are churches, mosques and a Jain temple in the area.

“It isn’t really about religion. It’s about community,” he said. “It’s about friendship and community, and you have to take the first step sometimes and build bridges. At times like this, you have to choose between fear and friendship. You have to make that choice.”

Afzal Khan, the MP for Manchester Gorton, tweeted: “Wonderful to see the solidarity shown by the people of Manchester with the Muslim community on this sad day. Thank you showing that we are stronger together.”