The Origin of Sin. The origin of sin is a universally commonly discussed problem of theology. It can be clarified only from the original texts of the Bible. There we find a clear answer by its diverse teachers: Sin originates from bodily desires. In our terminology, bodily desires are the biological instincts. In the animal world instincts are specifically restricted. They are only active in necessary times and conditions; they assurae the harmony of nature. Man’s instincts are free; they are always active and biologically unrestricted. The millionaire works for more money, women are able and ready to copulate even while being pregnant, the lust for power is limitless, and even world domination can not fulfil it. Remaining uncontrolled, instincts can destroy all human societies. They must be controlled morally. Man is personally responsible to keep them under God-given moral control. That is the dignity and tragedy of being human. Instincts are biological forces, morally neutral, but by nature self-centered. Godgiven morals are always altruistic. Under the guidance of strong morals, instinct is the force that brings good economy into reality, secures family life, a well trained society. When instinct escapes from under the control of morals, it is a guideless, selfcentered, always active force, which is able to destroy every social human activity, even personal life. Human morals are always questionable. My rules are as valuable as anyone else’s. Only God-given morals can be unquestionable. That is the meaning of the tree of the knowledge of good and evil: Man is free to do as he wishes, but moral laws are not under man’s will. To do what moral say is the personal and social responsibility of man. So there is a permanent battle between the moral convictions and the urgings of the instincts striving to get from under it. Consequently sin is the act of self-centered instincts getting out from under the guidance of the God-given moral rules.