Surah No. 5, Al Maaeda, Part of Ayat No. 6
وَإِن كُنتُمْ جُنُبًا فَاطَّهَّرُواْ وَإِن كُنتُم مَّرْضَى أَوْ عَلَى سَفَرٍ أَوْ جَاء أَحَدٌ مَّنكُم
مِّنَ الْغَائِطِ أَوْ لاَمَسْتُمُ النِّسَاء فَلَمْ تَجِدُواْ مَاء فَتَيَمَّمُواْ صَعِيدًا طَيِّبًا فَامْسَحُواْ
بِوُجُوهِكُمْ وَأَيْدِيكُم مِّنْهُ مَا يُرِيدُ اللّهُ لِيَجْعَلَ عَلَيْكُم مِّنْ حَرَجٍ وَلَـكِن يُرِيدُ
o لِيُطَهَّرَكُمْ وَلِيُتِمَّ نِعْمَتَهُ عَلَيْكُمْ لَعَلَّكُمْ تَشْكُرُونَ
If you are in a state of ceremonial impurity, bathe your whole body. But if you are ill or on a journey or one of you come from the offices of nature or you have been in contact with woman (Wife) and you find no water then take clean sand or earth and rub your face and then hands with it. Allah does not wish to place you in difficulty but to make you clean and complete His Favour to you that you may be grateful.
The things that make ghusl a must are:
1. After sexual inter course it is a must that a person had to perform total ablution (Ghusl).
2. When Menstruation and nifas period is over.
The Prophet (saws) said to Fatimah bint Hubaysh (ra): " When your period starts, stop praying, and when your period ends, perform ghusl then start praying again." ( Al-Bukhari)
How to perform the Ghusl :
Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states:
Tayammum can be performed under the following circumstances:
How to perform :
Find clean earth. Find a place where there is soil, sand or rock. Make sure that this place is clean and entirely free of all najasat (things which make one ritually unclean).
Make the intention ( Niyyat ). Before performing Tayammum, it is necessary to make its intention (niyyat).
Strike your hands on the ground. This act will most likely lift some dust. Brush it off and rub your face with your hands, beginning (as in Wudu) from the hairline to where the facial hair starts, and from the lobe of one ear to that of the other.
Strike your hands on the ground again. Brush off the dust of both hands. Use your left hand, rub your right arm from the fingertips up to the elbow, and back along the inner arm to the fingertips. Repeat this for your left arm.
Remember that once water becomes available, Tayammum is automatically invalidated.