The term sanctity of life means the extent to which human life is considered precious.
Jews believe that humans were made as part of God’s creation and in God's image. Therefore, human life should be valued and considered as sacred and God-given. Due to these attitudes towards the sanctity of life, Jews believe that only God can give life, and only God should take life away.
...Let not your heart convince you that the grave is your escape; for against your will you are formed, against your will you are born, against your will you live, against your will you die...Ethics of the Fathers 4:22
Murder is forbidden in Judaism as stated in the Torah.
Anyone who destroys a human life is considered as if he had destroyed an entire world, and anyone who preserves a human life is considered to have preserved an entire world.Talmud (Sanhedrin 37a)
The term pikuach nefesh refers to the belief stated in Jewish law that preserving human life should overrule any other religious considerations.
For example, if a human life is in danger of ending, then all other teachings in the Torah are overridden and all other laws are put aside to ensure everything is done to try and save the human life. There are a number of examples which can be found in the Talmud which discuss which mitzvot can be overridden if a human life is in danger.
What is meant by ‘the sanctity of life’?
The sanctity of life is the belief that life is precious and sacred. Jews believe that all human life is sacred because it is made in the image of God.