for the person who performs tayammum. Since he declared the person who performs tayammum purified, just as the person who performs ablution is purified, without restricting this to a particular time or saying that the end of the prayer time invalidates it—as he did state that the ability to use water invalidates it—this indicates that earth takes the place of water when water is unavailable. This is also what the foundational principles require.

Tayammum is a substitute for water, and a substitute takes the place of the original in its rulings, even if it differs in form. Thus, fasting two months substitutes for freeing a slave; fasting three days and seven days substitutes for the sacrificial offering required for tamattu‘ Hajj; and fasting three days as expiation for an oath substitutes for expiation through material means. A substitute takes the place of the original.

This conclusion is binding upon anyone who draws an analogy between tayammum and purification with water regarding their manner of performance, and consequently requires wiping up to the elbows, even though the verse concerning tayammum is unqualified. Similarly, ‘Ammār reasoned by analogy when he rolled in the dust as an animal rolls, wiping his entire body just as he would wash his entire body. The Prophet, may Allah bless him and grant him peace, explained that this analogy was invalid, and that the tayammum which suffices in place of ablution also suffices for purification from major ritual impurity: wiping the face and hands.

A substitute does not share the form of the original; rather, it shares its ruling. Tayammum consists of wiping two parts of the body—the two that are washed in ablution—while the two parts that are wiped are omitted. Tayammum for major ritual impurity is likewise confined to these two parts, unlike the full ritual bath. Tayammum does not involve rinsing the mouth or drawing water into the nose, unlike ablution; and tayammum