The Nazareth Community has been born out of St Martin-in-the-Fields and saw 47 people make membership promises on Sunday.
Those signing up include those who have known homelessness and those who are refugees.
The members have committed to sharing in five disciplines: silence, sacrament, service, sacred study and sharing.
Speaking of the new group Revd Dr Sam Wells, vicar at St Martin's said: "Being with God and one another and ourselves is how we shall spend eternity.
"The Nazareth Community is a group of people who are saying, 'Why not start eternity now? Why wait?' In their living eternal life now we see hope and inspiration for ourselves, our church, our community and our city."
Each new member of the community received a small Lampedusa Cross. Each cross was made on the island of Lampedusa from the wreckage of migrant boats washed ashore and is a sign of resurrection born in the pain and the hope of the cross.
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