An excerpt from Rabbi Kaplan's Handbook of Jewish Thought.
God has commanded us in His Torah, "Keep My decrees and laws, since it is only by keeping them that a person can [truly] live" (Leviticus 18:5). Thus, if one's life is in danger, he may violate any law to save or heal himself.
The only exception to this rule are the three cardinal sins -- idolatry, murder and sexual crimes -- for which one must die rather than transgress. We are called upon to give our lives rather than transgress any law which is even associated with these three sins.
It is therefore forbidden to resort to any idolatrous faith healer or shrine, even when one is dangerously ill and a psychological cure may be effected. One may receive treatment from a non-Jewish physician, even if he is an idolater, but not from an atheistic or idolatrous psychiatrist.
It is only forbidden to save a life through idolatrous means when some religious motivation is suspected. Where no religious motivation is involved, it is permitted to make material use of objects associated with idolatry to save a life. Therefore, it is permitted to heal with drugs used in idolatrous rites, or seek asylum in a church when one is being pursued.
One who is prepared to die for his Jewishness sanctifies God's Name. Conversely, denying that one is Jewish is akin to idolatry, since it implies a denial of our fundamental beliefs. Therefore, in time of danger, it is forbidden to save one's life by denying that he is Jewish. It is permitted to make an ambiguous statement, to act like a non-Jew, or to disguise oneself as such. It is forbidden to disguise oneself as a priest, however, since this is the same as an outright denial of one's Jewishness.
A woman may deny that she is Jewish or disguise herself as a nun to avoid being raped, since there is no sanctification of God's Name in being raped. In such a case, she may also disguise herself as a man…
Euthanasia and Abortion
One may remove the organ as soon as he stops breathing.
It is forbidden to destroy one life to save another. One may therefore not end a dying person's life by removing an organ needed for a transplant to save another. However, one may remove the organ as soon as he stops breathing, even though his heart is still beating, since the Torah considers life directly connected to breathing. This is brought out in the context of the Flood, regarding which it is written, "Everything on dry land whose life was sustained by breathing died" (Genesis 7:22). This is true only when the donor has no possible chance of living.
An unborn child is considered part of its mother's body and not a living person in its own right. Therefore, if a woman's life is endangered by childbirth, it is permissible to destroy the unborn child to save the mother's life. However, as soon as the child's head emerges or, in the case of a breech, the majority of its body, it is forbidden to destroy the child since it is considered a living person in its own right.
Nevertheless, it is forbidden to wantonly destroy even an unborn embryo, since it will eventually be born and live. Only when the physical or mental health of the mother is at stake, may she have an abortion. (For practical application, one must always refer to an expert in Jewish law - Ed.)
One is innocent of sin only when forced bodily or under threat of death to do a specific act, and only when the sin itself is the source of danger. However, it is forbidden to attempt to save oneself from sickness or danger by violating one of the three cardinal sins. In such cases, one is considered guilty, since he is not being coerced to transgress.
This distinction is also applicable in the case of money. It is forbidden to save one's life with another's money, unless one has the intention of repaying it. If one is forced under pain of death or torture to hand over another's money, however, he need not repay it, since it is considered involuntary. Still, if there is no direct coercion, and one saves life or limb with another's money, he must make restitution.
If one is being pursued or attacked and causes damage while escaping, he must therefore make complete restitution to everybody involved with the exception of his assailant. Where one causes damage by saving another's life, however, the courts exempt him from payment so that people should not hesitate to come to the rescue of others.
If someone comes to kill you, rise up and kill him first -- Talmud.
Although it is forbidden to save one life with another, it is permitted to kill in self-defense, since the assailant forfeits his life and there is no guilt in killing him. We are therefore taught, "If one comes to kill you, rise up and kill him first" (Talmud)
Even where the assailant does not directly threaten one's life, as with a burglar or armed robber, he may be killed in self-defense, where it may be assumed that he will kill if provoked. The Torah says, "If a burglar is caught in the act of breaking in, and is struck and killed, it is not considered an act of murder" (Exodus 22:1). We derive all cases of self-defense from this case.
Killing an Assailant
Just as one may kill in self-defense, so it is required to kill one who is pursuing or attacking another with murderous intent. Of course, if it is possible, one must save the person being pursued by injuring the attacker. Only when this cannot be done must we have no pity and kill the attacker.
Similarly, any assailant who might kill when provoked, such as a burglar or armed robber, must be killed by any bypasser to save the victim. Extending this to include all cases of endangering life, even a young child who does not know better, or an unborn baby, must be killed, since the life of the victim must be saved by any means.
We are taught that rape is equivalent to murder. Therefore, if one is attacking a woman with the intent of raping her, he may be killed to save her as long as he has not completed the act. Regarding a woman being sexually attacked, the Torah states, "Only the rapist shall be put to death… Since he attacked the betrothed girl in the field, even if she had cried out, there would have been no one to come to her aid" (Deut. 22:25, 27), which implies that if a rescuer is present, he may use any means to save her, even if it means killing the attacker. One may similarly save a man from homosexual attack.
An informer who denounces a fellow Jew to the government to be killed, imprisoned, or even fined is likened to an assailant, since being arrested can be a dangerous and traumatic experience. It is in recognition of this danger that the prophet lamented, "Your sons have fainted, they lie at the head of every street, as an antelope trapped in a net" (Isaiah 51:20). Therefore, one who is preparing to denounce another is considered an assailant, and may be killed as such as soon as his intention is know.
One who kills an assailant where he could have just as easily stopped him without taking his life, is considered a murderer.
In all the above cases, one should attempt to warn the assailant when possible. If he does not heed the warning, he should be stopped by being wounded or incapacitated, and only killed as a last possible resort. One who kills an assailant where he could have just as easily stopped him without taking his life, is considered a murderer.
One is only considered an assailant before he completes the act of murder, rape or informing. Once the deed is done, however, it becomes a case for the courts, and one may not take the law into his own hands.
A criminal whose activities endanger the community is considered an assailant, and after being duly warned, may be denounced to the authorities. If he accepts the warning, however, he cannot be denounced for his previous actions. This is true of anybody who endangers others, even without intent.
Any object that endangers life is judged as an assailant, and may be destroyed without monetary liability.
The commandment divides into two parts. "Cut off [the assailant's] hand" (Deut. 25:12) is a positive commandment to save a victim from the hands of his assailant. "Do not show any mercy" (ibid.) is a negative commandment not to hesitate to wound or even kill an assailant when necessary.
Saving Another Life
In any case, one who neglects to save a life when the opportunity presents itself is guilty of violating the commandment, "Do not stand still when your neighbor's life is in danger" (Leviticus 19:16). Therefore, one is obliged to spend any amount of money necessary to save a Jewish life, but the victim must repay it if and when he is able. Nevertheless, one need not endanger life or limb to save another.
If several persons are in danger where all cannot be saved, a religious scholar is given priority. Similarly, one should give precedence to his own parents or other relatives, as well as his teachers…
In all cases not involving a life or death situation, as for instance when a woman's honor is at stake, whether it be for food or clothing, she takes precedence [over a man], since the shame she could suffer is potentially greater.
Just as we are required to save a fellow Jew from danger, so too we must rescue any non-Jew who worships God, such as a Christian or Muslim. The Torah thus states, "Help him survive, whether he is a proselyte or a resident alien" (Leviticus 25:35). This implies that we are required to sustain these non-Jews and provide them with charity and food, as the Torah further states, "You may give it to a resident alien in your settlements so that he may eat it" (Deut. 14:21)…
Saving one's own life comes first.
One need not give his life to save another, as the Torah states, "Let our brother live alongside you" (Leviticus 25:36), which implies that one's own life comes first. Therefore, for example, if two persons are in a desert, and one has just enough water for himself, he need not share it with the other.
Similarly, one need not endure excessive pain or suffering to save another's life. Although it is not required, it is an act of piety to give one's life to save a community or a great religious leader.
There is nothing more precious and irreplaceable than life in the eyes of God. Therefore, one who saves a single life is counted as if he had saved the entire world.
From "The Handbook of Jewish Thought" (Vol. 2, Maznaim Publishing. Reprinted with permission.