Sacrifice may be divided into two categories, one that is desirable, and the other that is obligatory.
As for the desirable one, an example of it is that which is required of pilgrims who perform Hajj only (Hajj Ifrad), or who perform ‘Umrah only. As to the obligatory sacrifice it may be one of the following:
1. That which is obligatory for those performing Hajj Iqran (combining Hajj and ‘Umrah without a break in between),
2. or Hajj Tamattu’ (combining Hajj and ‘Umrah but with a break in between).
3. That which is obligatory for a pilgrim who misses out an essential ritual of Hajj, e.g., throwing pebbles, or putting on ihram from a miqat (a place designated for entering into a state of ihram), or combining day and night while camping at Arafah, or spending the night at Muzdalifah or Mina or departing Makkah without performing Tawaf al-Wida’ (Farewell circumambulation).
4. That which is obligatory for a pilgrim committing something forbidden in the state of ihram, other than sexual intercourse, wearing perfume or shaving.
5. That which is obligatory for committing a crime within the sacred precincts of Haram, like hunting or cutting trees within the Sacred precincts of Haram. All these have been explained above in their respective sections.