Short answer
Najasah is a physical impurity, like urine or blood, on your body, clothes or place, and it is removed by washing. Hadath is a state you are in, minor (needing wudu) or major (needing ghusl), and it is lifted only by wudu, ghusl or tayammum. Prayer needs freedom from both.
Hadath is a legal impurity of the person, lifted by wudu, ghusl or tayammum. Najasah is a physical impurity, removed by water and, in the Hanafi school, by any pure liquid that removes it, such as vinegar. No intention is needed to remove najasah.
Other madhhabs
- Shafi'i
- Najasah can only be removed with water; other liquids such as vinegar do not purify. Intention is fard for wudu and ghusl.
- Maliki
- Only water removes najasah, and intention is fard for wudu and ghusl.
- Hanbali
- Only water removes najasah, and intention is fard for wudu and ghusl.
Explanation
Both words are often translated as impurity, which causes confusion. Najasah (also najis or najas) is something real you can wash: urine, stool, blood, vomit. Hadath is not a thing on you at all; it is a ruling that you are not in a state of purity, because you used the toilet, slept or passed wind, or, for major hadath, had intercourse or a period. In Malay and Indonesian they are called najis and hadas.
Side by side:
- What it is: najasah is a substance; hadath is a state.
- Where: najasah can be on the body, clothes or place of prayer; hadath is on the person only.
- How it is removed: najasah by washing until gone; hadath by wudu, ghusl or tayammum.
- Intention: not needed to wash off najasah; needed for tayammum, and sunnah for wudu and ghusl in the Hanafi school.
- Tayammum: lifts hadath when water is not available, but never removes najasah.
So you can have wudu with urine on your trousers (no hadath, but najasah), or perfectly clean clothes while needing ghusl (major hadath, no najasah). Touching najasah does not cause hadath: see touching najis. And the body of a person in janabah is not impure.
Salah needs both: freedom from hadath, and from najasah beyond the excused amount. For the types of impurity, see types of najis, and for what major hadath forbids, see janabah.
The evidence
Quran, Surah Al-Maaida 5:6
يَٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوٓا۟ إِذَا قُمْتُمْ إِلَى ٱلصَّلَوٰةِ فَٱغْسِلُوا۟ وُجُوهَكُمْ وَأَيْدِيَكُمْ إِلَى ٱلْمَرَافِقِ وَٱمْسَحُوا۟ بِرُءُوسِكُمْ وَأَرْجُلَكُمْ إِلَى ٱلْكَعْبَيْنِ ۚ وَإِن كُنتُمْ جُنُبًۭا فَٱطَّهَّرُوا۟ ۚ وَإِن كُنتُم مَّرْضَىٰٓ أَوْ عَلَىٰ سَفَرٍ أَوْ جَآءَ أَحَدٌۭ مِّنكُم مِّنَ ٱلْغَآئِطِ أَوْ لَٰمَسْتُمُ ٱلنِّسَآءَ فَلَمْ تَجِدُوا۟ مَآءًۭ فَتَيَمَّمُوا۟ صَعِيدًۭا طَيِّبًۭا فَٱمْسَحُوا۟ بِوُجُوهِكُمْ وَأَيْدِيكُم مِّنْهُ ۚ مَا يُرِيدُ ٱللَّهُ لِيَجْعَلَ عَلَيْكُم مِّنْ حَرَجٍۢ وَلَٰكِن يُرِيدُ لِيُطَهِّرَكُمْ وَلِيُتِمَّ نِعْمَتَهُۥ عَلَيْكُمْ لَعَلَّكُمْ تَشْكُرُونَ ﴿٦﴾
O you who have believed, when you rise to [perform] prayer, wash your faces and your forearms to the elbows and wipe over your heads and wash your feet to the ankles. And if you are in a state of janabah, then purify yourselves. But if you are ill or on a journey or one of you comes from the place of relieving himself or you have contacted women and do not find water, then seek clean earth and wipe over your faces and hands with it. Allah does not intend to make difficulty for you, but He intends to purify you and complete His favor upon you that you may be grateful.
The ayah of wudu, ghusl and tayammum, which lift hadath.
Quran, Surah Al-Muddaththir 74:4
وَثِيَابَكَ فَطَهِّرْ ﴿٤﴾
And your clothing purify
The command to remove najasah from clothing.
Sahih Muslim 224
Sahih... لا تقبل صلاة بغير طهور ...
"No prayer is accepted without purification."
Purity is a condition of prayer.
Where the ruling is recorded
- al-Hidaya, Kitab al-Taharat, chapter on impurities and their purification. Impurity may be removed with water or any pure liquid that removes it.
- Nur al-Idah with Maraqi al-Falah, Kitab al-Taharah, opening chapters. Distinguishes purification from hadath and from najasah.
- al-Majmu' (Nawawi), Kitab al-Taharah, chapter on removing impurity. Only water purifies in the Shafi'i school.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.