Al-lhsar (as used in the Qur’an) means blocking the path to the House of Allah. Allah says, (And complete the Hajj or `Umrah in the service of Allah. But if you are prevented (from completing it) send an offering for sacrifice.) (Al-Baqarah 2:196)

Sheikh Sayyed Sabiq states in his well-known book, Fiqh Us-Sunnah: The verse of ihsar was revealed at the time of Hudaybiah when the Prophet (peace and blessings be upon him) was prevented from visiting the Sacred Mosque. By implication it means being prevented from making Tawaf in the case of `Umrah, or spending the Day at `Arafah and making Tawaf Al-lfadah in the case of Hajj.

There is disagreement among the scholars, however, on what constitutes a state of prevention or blocking. Malik and Shafi`i hold that such a state refers to a blockade by an enemy, for the verse was revealed about the Prophet (peace and blessings be upon him), who was blocked from performing an `Umrah. Ibn `Abbas also holds a similar view. Most scholars, including the Hanafis and Ahmad, however, are of the opinion that a person is deemed blocked when he is prevented from approaching the House of Allah by reason of an enemy force (a force of disbelievers or a rebel group) or a sickness that could worsen by motion or travel, a state of fear (and insecurity), loss of provisions, or in the case of a woman, the death of her mahram accompanying her, or any other similar cause. Ibn Mas`ud even gave a verdict that a man bitten by a snake is also considered among the prevented ones.

These scholars base their argument on the fact that the words (But if you are prevented) used in the above Qur’anic verse about the Prophet (peace and blessings be upon him) are general and are not limited to any specific cause of prevention. This is the strongest view on this subject.