Describe the Teachings of Christianity about the Sanctity of Life in Relation to Euthanasia

Euthanasia comes from the Greek meaning 'easy death'. Formally known as 'mercy killing' it is the act of making or helping someone to die rather than letting him or her die naturally, because if they die naturally they will be in considerable pain or will have an extremely poor quality of life.
There are several ways it can be classified:
Voluntary Euthanasia meaning the dying patient or their legal representative requests euthanasia.
Passive Euthanasia meaning allowing someone to die without doing anything to prevent his or her death.
Positive Euthanasia meaning taking deliberate action to cause a death for example withdrawing treatment.
Active Euthanasia meaning giving a lethal injection or using some other method to actively bring about a death.
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