Apostasy, which is the rejection of Islam by word, deed, or omission, must bring repentance within a specified time or the death penalty is imposed. Transgression or revolt against the ruler by use of force is to be met by the force of the ruler, and if the transgressors are killed in battle that is their punishment. Those who do not fight or who surrender or are peaceably arrested will be punished at the discretion of the judge for a crime less severe than Hudud. Those who fight until subdued are to be executed. If it can be shown that the revolt is against a ruler who has transgressed the law of Islam, then no punishment is to be issued. Theft carries the penalty of the severance of the right hand, providing it can be shown the defendant had the clear intent of acquiring the stolen property without the victim's consent. The property must have been carried away from where it is usually kept. Further, the property must be valued in Islam (e.g., alcohol and pork have no value). If there is some doubt about the guilt of the defendant, the punishment is lessened. Highway robbery involves direct confrontation with the victim. Penalties for this offense include severing of the right hand and the left foot or imprisonment. Fornication by unmarried persons is punished by flogging with 100 stripes, and adultery has the additional punishment of stoning to death. Four eyewitnesses are required for conviction of adultery or a confession by the adulterer. A charge of adultery without the four eyewitnesses to support the charge is considered slander and is punished with 80 stripes. The drinking of alcohol is punishable by flogging. Physical punishments are considered to be more effective in deterring Hudud crimes than imprisonment.