The statement's been released in response to proposed legislation by Lord Falconer which will be debated on Friday.
It says: "As leaders of faith communities, we wish to state our joint response to Lord Falconer's Assisted Dying Bill.
"We do so out of deep human concern that if enacted, this bill would have a serious detrimental effect on the wellbeing of individuals and on the nature and shape of our society.
"Every human life is of intrinsic value and ought to be affirmed and cherished.
"This is central to our laws and our social relationships; to undermine this in any way would be a grave error.
"The Assisted Dying Bill would allow individuals to participate actively in ending others' lives, in effect colluding in the judgment that they are of no further value. This is not the way forward for a compassionate and caring society.
The letter comes just days after former Archbishop of Canterbury announced he's changed his mind on the issue and was supporting a change in the law.
Along with the Most Revd Justin Welby, this statement's been signed by Chief Rabbi Ephraim Mirvis, Dr Shuja Shafi of the Muslim Council of Britain and Lord Indarjit Singh of the Network of Sikh Organisations.
The Deputy Moderator of the Free Churches Group, Revd Jonathan Edwards, signed the letter and spoke to Premier's Marcus Jones on the News Hour:
You can listen to the full interview on News Hour catch up here.