Thousands of people packed in St Paul's Cathedral for a farewell service to Rt Rev Richard Chartres on Thursday night.
The Bishop of London has been in the post for 22 years and retires later this month.
A formal eucharist was attended by clergy and representatives of a number of Christian denominations, with Chartres hailing the gathering as "a symbol of unity".
Outside the Cathedral hundreds more met around a "pop-up cathedral" with King's Cross Church offering worship and the Bishop of Edmonton presiding over a more informal alternative celebration.
The Bishop of London told Christian Today before entering the Cathedral: "For too long we have expected people to come to us. Increasingly we have got to go to them."
He said he leaves the number three job in the Church of England at a time of "promise and peril".
He added: "What we are offering is not just one more ideology in the noisy marketplace where salesman for various ideologies are trying to drown each other out.
"What we are offering is a community in which the spirit of Jesus Christ dwells and a community which brings people together rather than prising them apart.
