Self-sacrifice is when someone is willing to give up their own life in order to fulfill a commandment or protect God's name. In Jewish law, there are certain situations where self-sacrifice may be required, such as if someone is being forced to commit a sin or deny their faith. This is considered a very serious decision and requires careful consideration and consultation with experts in Jewish law. The act of self-sacrifice is seen as a noble and courageous act, but it is not taken lightly and should only be done in extreme circumstances.