Thousands descended on central London for a vigil ahead of the ceasefire vote.
People of all nationalities and religions came together for a moment of peace, opposite Downing Street, following the outbreak of the Israel-Gaza war.
Christian, Muslim and Jewish leaders as well a Labour and a Lib Dem MP gave speeches calling to end the violence.
The ceasefire vote was defeated by 125 votes to 294.
It called for an end to the “collective punishment of the Palestinian people” and urged “all parties to agree to an immediate ceasefire”.
The vote was supported by 56 Labour rebels who joined other opposition parties to demand a ceasefire, against the Conservatives who opposed it.
In central London, Rabbi Josh Levy, co-leader of Progressive Judaism, said ahead of the vote: “It’s a hugely important sight. Certainly many of us feel that we’ve needed this over the course of the last few weeks.
“This moment of coming together. We have much more in common than we do that divides us. Even in the heart of the pain of this moment.
“This event was about making that statement, and that we need to look after each other.”
Magnen Inon, whose parents were murdered by Hamas on 7 October, told BBC London: “Our shared future is based on the belief that all human beings are equal, and deserving of respect and safety.
“This is how I was raised and how I am raising my own children.”
Julie Siddiqi, Muslim co-organiser and a faith-relations consultant, said: “It’s been very emotional. Looking over and seeing everyone who has made a point of coming.
“It shows and reminds me that there is more humanity not hatred.
“People don’t want this binary nastiness and it’s really important for us to come together and show that we can cut through that with hope.”
Rabbi Charley Baginsky, co-leader of Progressive Judaism, added: “I don’t think people are going to get over their grief by seeing this [vigil] but they can see that we can stand together in our grief.
“We have different starting places for our grief but we need to reminded that we are human, and we are friends and we need to hold each other in this moment.”
Sheikh Ibrahim Mogra, senior Muslim leader, said: “Tonight I’m feeling very hopeful. The number of people who have turned up today is a demonstration that people genuinely want us to get along.
“Our hearts are all broken, but there is hope when we can recognise each others grief and pain and speak out against any hatred that will divide our communities.
“Standing together we have a remedy to patch things up between our communities who have lived together for decades.
“We have friendships and good relations between religions in this country and we can’t allow that to be taken away from us.”
Asad Ahmad, BBC London lead presenter
The rally is a fraction of the size of weekend protests, but it is midweek and a working day for many who might otherwise like to be here.
Nevertheless, thousands of people have come to Westminster to voice their support for a ceasefire and the numbers are swelling.
Crowd made up of Christians, Muslim, Jews, people of other faiths and none faith. All ages and colours.
A minutes silence has been held for victims on both sides of the war and I’ve seen Imams and Rabbi’s hugging each other in the name of humanity.