The Assisted Suicide (Scotland) Bill would allow Scots aged 16 or over to be prescribed lethal drugs, if they have a terminal illness with no prospect of improvement, and they think their quality of life is unacceptable.
Supporters say the plan has received backing from the public, but critics, including the Christian charity CARE, argue it sends the wrong message.
James Mildred is from CARE, and said the bill tells people who are terminally ill but do not want to die that they are a burden.
He told Premier's News Hour: "What kind of message does this send out to vulnerable people, to disabled people, to people with terminal illnesses - with all of the complexities and challenges that those situations bring?
"What kind of message are we sending to them?
"We're effectively saying if you get to a point when it all becomes too much, it's okay. You can just end your own life.
"Surely it's better as a society, surely it's more compassionate and caring to say to people who're suffering towards the end of their life, who're suffering for whatever reason, that we are here to help and we're going to do everything we can to give you the best quality support that this country can give you."
Listen to Premier's Hannah Tooley speak to James Mildred here:
CARE for Scotland National Director Stuart Weir said: "We are delighted many MSPs have voted against the principles of this dangerous and unnecessary legislation.
"Scotland is a compassionate society, with a proud tradition of caring for people and protecting the most vulnerable.
"The assisted suicide bill before MSPs was poorly drafted and as the Health and Sport committee said, contained numerous flaws.
"In fact it has been repeatedly criticised by leading doctors, ethicists, lawyers and faith groups.
"Our focus now should be on devoting resources, time and talents to further developing end of life care across Scotland and on sending a positive, compassionate message to vulnerable and disabled people that we are going to help them to live, not to die."
