"Najasat" (pl. najasat) means uncleanliness, im*!purity.
In Islamic laws, the najasat is of two types: inherent and acquired. To differentiate between the two, a thing which is inherently unclean is known as "`ayn najis," whereas a thing whose uncleanliness is acquired is known as "najis". A pure thing acquires impurity by coming into contact with one of the `ayn najis. For example: blood is considered an `ayn najis, whereas milk is considered pure. Now, if a drop of blood falls into a glass of milk, the milk will become najis because of the blood which is an `ayn najis.
The plural of `ayn najis is "a`yan najisah."
"Taharat" is opposite of "najasat," it means cleanli*!ness and purity.
"Tahir" is opposite of "najis," it means a thing which is clean and pure.
B. THE A`YAN NAJISAH
(THE INHERENTLY UNCLEAN THINGS)
According to the Islamic laws, the a`yan najisah are nine in number. The nine a`yan najisah can be divided into four groups as follows:
i. Common between Men & Animal:
1. urine;
2. stool;
3. semen;
4. blood;
5. corpses;
ii. In Animals only:
6. dogs;
7. pigs;
iii. In Man only:
8. kafir;
iv. Drinks:
9. intoxicating liquids.
The implication of this law for a Muslim is that he or she must refrain from the a`ya najisah in three things: acts of worship, food and drink.
In the following pages, we shall explain the rules regarding the nine inherently impure things.
1. & 2. URINE AND STOOL
The urine and stool of human beings are `ayn najis.
Most people of the world consider urine and stool as unclean, but Islam has gone one step further in declaring them to be ritually unclean. For example, in the matters of worship a Muslim who has passed urine or emptied his bwels cannot pray even after cleaning his body from urine and stool-he must also do wudu, a minor ablution which will be discussed in chapter 2.
The Islamic shari'ah has prescribed certain rules on how to cleanse oneself of urine and stool.
1. The organ of urination can be made tahir only by the pouring of water on it at least twice. It is better to wash it three times.
2. As far as the anus is concerned, a person can clean himself/herself with water, or with three pieces of papers, or three pieces of rags or three stones. The papers, rags and stones can be used only if the anus is not more than normally dirtied, i.e., the excrement has not spread more than normal. If the area dirtied is large, or the excrement is mixed with some other najasat like blood, then only water can be used to purify oneself.
However, it is always better to wash oneself with water. While praising the people who built Masjid Quba, Allah says, "Therein are men who love to cleanse them*!selves; and Allah loves those who cleanse themsel*!ves." (9:108) When this verse was revealed, the Prophet asked the people of Quba, "What do you do when clean*!ing yourselves that Allah has praised you for it?" They said, "We cleanse ourselves after emptying the bowels with water." [3]
3. In case of cleaning oneself with three pieces of papers, rags or stones, it is obligatory to use all the three pieces even if the body becomes clean by one or two of them. However, if the body is not clean even after using the three pieces, then extra pieces must be used till the body becomes clean.
4. It is recommended for men to do istibra' after urinating. Istibra' means to clean something, to get rid of something. Here it means getting rid of the remaining drops of urine from penis. The method of istibra': Squeeze with the middle-finger of the left hand from the anus to the root of the penis three times; then holding the penis between the thumb and the fore-finger, squeeze three times from the root up to the glans; and squeeze the glans itself three times.
The benefit of istibra': If a liquid comes out of a man's penis after urinating and he doubts whether this is urine or something else, then he can assume it to be tahir if he has done istibra'. But if he has not done istibra', then he must consider it najis.
5. In western toilets, there is no water, only tissue paper is available. As far as stool is concerned, it can be cleaned with tissue paper as explained above. In case of urinating, would it be enough to wipe the related part with tissue paper? No, wiping with tissue paper would not purify the organ of urination. Nonetheless, in such a case, one should do istibra' and then wipe the organ with tissue paper, and later on when it becomes possible, he or she must purify the organ with water. The benefit of istibra' and wiping with tissue paper is that the organ will become dry and not make the underwear or the thighs najis.
However, in the above case, if the person's private parts sweat, then he or she must purify the organ, the immediately surrounding area and the underwear with water. `Ays bin al-Qasim asked Imam Ja'far as-Sadiq (as) about a person who urinated in a place where there was no water and so he dried his penis with a stone, but later he started sweating in the same area. The Imam said, "He should wash his penis and thighs." [4]
6. While urinating or emptying the bowels, it is neces*!sary to conceal one's private parts from the on-lookers. This condition is easily taken care of in normal toilets, but one must be careful while on the call of nature in an open area, e.g., during a picnic or while travelling, etc.
7. A Muslim should also realize that even for such a trivial thing as using toilet, Islam emphasizes that either you must be the owner of the washroom or you must have the permission of the owner; otherwise, it will be haram for you to fulfill your natural needs in that place.
8. It is haram to face the qiblah or to keep the qiblah on the back side while urinating or evacuating the bowels. Qiblah means the direction of the Ka'bah (Mecca). There*!fore, a Muslim must make sure that the toilet of his house is not built in such a way that when he sits on the toilet, his front or back side is towards the qiblah. If the cir*!cumstances make it necessary to use a toilet on which a person will either be facing the qiblah or will have his back towards it, then he should refrain from facing the qiblah.
* * *
The urine and excrement of the animals are also najis if they belong to the group of animals (1) whose meat is forbidden in Islam and (2) whose blood spurts out when a blood-vessel is cut. Therefore, if these two conditions are not found together in an animal, its urine and excre*!ment are not najis. For example, even though its blood spurts out, sheep's urine and stool are not najis because it's meat is not forbidden.
However, the droppings of all the birds are tahir.
What should a person do if he finds animal stool or excrement on his dress or person and doesn't know from which type of animal it originated? In all the cases of ignorance and doubt, one can assume that it came from an animal whose urine or excrement is tahir.
Abu Agharr an-Nahhas, a veterinarian, said to Imam Ja'far as-Sadiq (as): "I treat the animals. Sometimes I have to go (to treat them) at night. The animal may have urinated and emptied its bowels; and when it jumps on its own refuse and urine, it splashes on my dress. Then in the morning, I see its trace on my dress. [What should I do?]" The Imam said, "There is nothing on you." [5] This answer can be explained in two ways: Abu Agharr could assume that his dress was still pure because in the darkness of night he could not have been sure of what come on his dress, or because the animals were domesticated and thus their refuse and urine is not najis.
3. SEMEN
Semen is also one of the `ayn najis.
There are many ahadith on this issue, but here I will just describe a historical event and its relevant Qur'anic verse which proves that semen is najis.
In the battle of Badr, the unbelievers of Mecca had camped near the spring of Badr and the ground of their camp-site was firm. On the other hand, the Muslims were far from the spring and thus experienced difficulty in getting water; and the ground under them was sandy which made their stand and manoeuvres difficult. To make the matters worse, many of the Muslims had noc*!turnal discharge in their sleep and became impure (najis). Then came Allah's help which the Qur'an describes as follows:
And (remember) when He spread a cover of drowsi*!ness over you as a security from Him (and thus you slept peacefully). And He sent down upon you water from heaven to purify you with it, to take away from you the unclean (insinuation) of the Shaytan, to strengthen your hearts and to plant you feet firmly with it. (8:11)
The words relevant to our subject are: "He sent down upon you water from heaven to purify you with it." The least that this verse proves is that semen is najis, and with its discharge a man becomes ritually impure.
`Abdullah ibn Abi Ya'fur asked Imam Ja'far as-Sadiq (as) about a dress which had come into contact with semen. The Imam said, "If you know the particular part of the dress which came into contact with semen, then wash that area only; but if that part is unknown to you, then wash the whole dress." [6]
* * *
Sometimes a liquid, other then semen and urine, is discharged from man; this type of liquid is not najis. These liquids are of three types:
1. Mazi: a whitish liquid which is discharged from penis during sexual fore-play.
2. Wazi: a liquid which comes out after the discharge of semen.
3. Wadi: a liquid which comes out after urinating.
All these discharges are tahir.
4. BLOOD
Blood of human being is najis.
Blood of the animals whose blood spurts out is also considered najis. But the blood of an animal whose blood does not spurt out is tahir, e.g., the blood of fish or the body-fluid of a mosquito. Ibn Abi Yafur asked Imam Ja'far as-Sadiq (as), "What do you say about the blood of fleas?" The Imam said, "There is no objection in it." Ibn Abi Ya'fur, "Even if it is more and excessive?" The Imam, "Yes, even if it is more." [7]
After an animal has been slaughtered and the normal amount of its blood has flowed out, the blood remaining in its body is tahir.
The blood found in an egg is also najis.
If there is blood on someone's dress or on his person and he doubts whether it is of an animal whose blood spurts out or not, then he should consider it tahir.
If a yellowish liquid comes out of a wound and one doubts whether it is blood or something else, then he should consider it tahir.
Even though blood is considered najis, one is still permitted to donate or sell his blood. Doctors, nurses, and scientists can work and experiment with blood. The only important thing is that at the time of praying, one's body and dress must be free from this najasat.
5.CORPSES
The dead body of a Muslim becomes najis after becoming cold and before being washed (ghusl mayyit).
al-Halabi asked Imam Ja'far as-Sadiq (as) about a person whose dress had fallen upon the body of a dead human being. The Imam said, "If the dead body had been given the ritual bath (ghusl mayyit), then there is no need to wash your dress which touched it; but if the body had not been given the ritual bath, then wash whatever part of your dress that had touched it." [8]
A kafir is najis both during his life-time and after his death.
If a part of a living human being's body or of a living animal's body is cut off, it will be considered najis. This law, however, does not apply to the dry skin which comes off the lips or the skin which comes off from a healing wound, or pimples, dandruff, etc.
A miscarried fetus is also najis.
* * *
"Dead body-maytah" in case of the animals means: an animal which had died naturally or was slaughtered in a non-Islamic way.
The dead body of an animal whose blood spurts out is also najis with the exception of those of its parts which have no life (feeling) in them during life-time, e.g., hair, nails, bones, beak, horn and teeth. Of course, these parts become najis by being in contact with the dead body; so after separating them from the animal's body they must be purified.
The dead body of the animal whose blood does not spurt out is tahir; for example, a dead fish. `Amman as-Sabati says that Imam Ja'far as-Sadiq was asked about a beetle, a fly, a locust, an ant and other similar things that die in a well, oil, butter or other such things: The Imam answered, "There is no objection concerning all (the animals) that do not have (spurting) blood." [9]
If someone buys a dress, a belt, or a wallet, etc, made of an animal's skin and does not know for sure whether or not the animal was slaughtered Islamically, then in such a case there are two possibilities:
1. Either he has bought it from a Muslim or from a Muslim market, then he can assume that the animal was slaughtered according to the shari'ah.
2. Or he has bought it from a kafir. In such a case if there is a probability that the skin or hide has been taken from an animal which was slaughtered ac*!cording to the shari'ah, then he can consider it tahir and use it. However, he still cannot use such a thing in salat (prayers). And if there is no such probability, then he cannot consider it tahir, it should be regarded as najis.
http://www.al-islam.org/ritualandspiritual/2.htm