The Archbishop of Canterbury together with the president of the Catholic Bishops Conference of England and Wales, and The Chief Rabbi of the United Hebrew Congregations of the Commonwealth have warned of the risk to vulnerable people the Assisted Dying Bill poses.
In a joint letter, Most Rev Justin Welby, Cardinal Vincent Nichols and Rabbi Ephraim Mirvis have appealed to "people of all faiths and none" to join with them "through the 'common bond of humanity' in caring for the most vulnerable in society."
Their remarks come as the Assisted Dying Bill is due to have its second reading in the House of Lords on Friday.
The Bill, tabled by Baroness Meacher, seeks to legalise assisted suicide for people with under six months to live.
It would mean that terminally ill, mentally competent adults will be able to request assistance to die depending on the approval of a High Court judge and two doctors.
The letter reads: "By the faiths we profess, we hold every human life to be a precious gift of the Creator, to be upheld and protected.
"All people of faith, and those of none, can share our concern that the common good is not served by policies or actions that would place very many vulnerable people in more vulnerable positions.
"We appeal to people of whatever faith or belief to join us through our common bond of humanity in caring for the most vulnerable people within our society.
"In contrast to the proposals in this Bill, we continue to call for measures to make high-quality palliative care available to all at the end of their lives.
"We believe that the aim of a compassionate society should be assisted living rather than an acceptance of assisted suicide."
Last month, the British Medical Association moved its stance on assisted dying from 'opposed' to 'neutral' with 49 per cent of members voting in favour and 48 per cent voting against it.
In 2015, an attempt to change the law on assisted dying was defeated in Westminster.