As thousands of Londoners gathered at Trafalgar Square to celebrate Diwali, Sadiq Khan said Londoners must "respect, celebrate and embrace each other" to face the challenges ahead.
Addressing the crowds on Sunday (October 16) who braved the rain to mark the ancient Hindu festival of light, the Mayor of London said diversity is a strength which mustn't weaken.
Mr Khan said: "The message of Diwali is so important.
"Light triumphs over darkness, love over hate.
"And diversity is our greatest strength."
Speaking on the main stage at the event, he added: "There are challenges ahead, there are people who want to divide our communities.
"Are we going to allow them? I think diversity is a strength and the great thing about London is, we don't simply tolerate each other."
Although it is a Hindu festival, Sikhs, Jains and Londoners of all generations and beliefs descended into central London to enjoy the festivities.
Stalls of food, drink as well as dance performances and henna stands delighted visitors who revelled in the celebrations.