Tayammum

Allah SWT reveals, "Hei faithful ones, when you are about to pray shalat, wash your face and your hands until your elbows, and wipe your heads and (rinse) your feet up to your ankles. And if you are junub, then bathe, and if you are sick or traveling in a journey, or returning from washroom (toilet) or touching a woman, then you cannot find water,  so do tayamum with good (clean) dirt wipe your face and hands with that dirt. Allah is not going to burden you, but He wants you to clean and He will perfect His comfort for you, so that you will be grateful.(Al-Maidah : 6)
Rasulullah SAW explained, "I am esteemed over other humans with three matters, first: our rows during shalat prayers are made similar to those of the angels, second: all earths are made as mosque for us, and third: the ground is made pure when we cannot find water."(HR. Muslim and Khazin, Page. 417, juz/section 1)